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Table Of Contents
Release Notes for the Cisco 800 Series Routers for Cisco IOS Release 12.3(2)XC3
Determining the Software Version
Upgrading to a New Software Release
New Software Features in Release 12.3(2)XC3
New Software Features in Release 12.3(2)XC2
New Software Features in Release 12.3(2)XC1
New Software Features in Release 12.3(2)XC
New Software Features in Release 12.3(2)T
Resolved Caveats - Release 12.3(2)XC3
Resolved Caveats - Release 12.3(2)XC2
Resolved Caveats - Release 12.3(2)XC1
Resolved Caveats - Release 12.3(2)XC
Open Caveats - Release 12.3(2)XC
Cisco Product Security Overview
Reporting Security Problems in Cisco Products
Obtaining Technical Assistance
Cisco Technical Support Website
Definitions of Service Request Severity
Obtaining Additional Publications and Information
Release Notes for the Cisco 800 Series Routers for Cisco IOS Release 12.3(2)XC3
February 7, 2005
These release notes describe new features and significant software components for the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers that support Cisco IOS Release 12.3 T, up to and including Release 12.3(2)XC3. These release notes are updated as needed to describe new memory requirements, new features, new hardware support, software platform deferrals, microcode or modem code changes, related document changes, and any other important changes. Use these release notes with the Cross-Platform Release Notes for Cisco IOS Release 12.3(2)T located on Cisco.com.
For a list of the software caveats that apply to Release 12.3(2)XC3, see the "Caveats" section, and refer to the online Caveats for Cisco IOS Release 12.3(2)T document. The caveats document is updated for every 12.3 T maintenance release and is located on Cisco.com.
Contents
These release notes provide information about the following topics:
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Caveats
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System Requirements
This section describes the system requirements for Release 12.3(2)XC3 and includes the following sections:
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Memory Requirements
This section describes the memory requirements for the Cisco IOS feature sets that are supported by Cisco IOS Release 12.3(2)XC3 on the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers.
Table 1 Recommended Memory for the Cisco 828, 831, 836, and 837 Routers
mum
mumCisco 827-4V
Cisco 827-4V Series IOS IP/Voice
IP/Voice
c820-v6y6-mz
12 MB
12 MB
32 MB
48 MB
Cisco 827-4V Series IOS IP/Voice Plus
IP/Voice Plus
c820-sv6y6-mz
12 MB
12 MB
48 MB
48 MB
Cisco 827-4V Series IOS IP/FW/Voice
IP/FW/Voice
c820-ov6y6-mz
12 MB
12 MB
48 MB
48 MB
Cisco 827-4V Series IOS IP/FW/Voice Plus 3DES
IP/FW/Voice Plus 3DES
c820-k9osv6y6-mz
12 MB
12 MB
48 MB
48 MB
Cisco 828
Cisco 828 Series IOS IP
IP
c828-y6-mz
8 MB
8 MB
20 MB
32 MB
Cisco 828 Series IOS IP/FW
IP/FW
c828-oy6-mz
8 MB
8 MB
20 MB
32 MB
Cisco 828 Series IOS IP Plus
IP Plus
c828-sy6-mz
8 MB
8 MB
24 MB
32 MB
Cisco 828 Series IOS IP/FW Plus 3DES
IP/FW Plus 3DES
c828-k9osy6-mz
8 MB
8 MB
32 MB
32 MB
Cisco 831
Cisco 831 Series IOS IP/FW IPSec 3DES
IP/FW2/IPSec 3DES
c831-k9o3y6-mz
8 MB
12 MB
32 MB
48 MB
Cisco 831 Series IOS IP/FW Plus IPSec 3DES
IP Plus/FW2/IPSec 3DES
c831-k9o3sy6-mz
8 MB
12 MB
48 MB
48 MB
Cisco 836
Cisco 836 Series IOS IP/FW IPSec 3DES
IP/FW2/IPSec 3DES
c836-k9o3y6-mz
8 MB
12 MB
32 MB
48 MB
Cisco 836 Series IOS IP/FW Plus IPSec 3DES
IP Plus/FW2/IPSec 3DES
c836-k9o3sy6-mz
8 MB
12 MB
48 MB
48 MB
Cisco 836 Series IOS IP/FW/Dial Backup Plus IPSec 3DES
IP Plus/FW2/Dial Backup IPSec 3DES
c836-k9o3s8y6-mz
8 MB
12 MB
48 MB
48 MB
Cisco 837
Cisco 837 Series IOS IP/FW IPSec 3DES
IP/FW2/IPSec 3DES
c837-k9o3y6-mz
8 MB
12 MB
32 MB
48 MB
Cisco 837 Series IOS IP/FW Plus IPSec 3DES
IP Plus/FW2/IPSec 3DES
c837-k9o3sy6-mz
8 MB
12 MB
48 MB
48 MB
1 Recommended memory is the memory required considering future expansions.
Hardware Supported
Cisco IOS Release 12.3(2)XC3 supports the following routers:
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For detailed descriptions of new hardware features and which features are supported on each router, see the "New and Changed Information" section. For descriptions of existing hardware features and supported modules, see the hardware installation guides, configuration and command reference guides, and additional documents specific to the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers, which are available on Cisco.com at the following location:
http://www.cisco.com/univercd/cc/td/doc/product/access/acs_fix/800/index.htm
This URL is subject to change without notice. If it changes, point your web browser to Cisco.com, and click the following path:
Cisco Product Documentation: Access Servers and Access Routers: Fixed Access: Cisco 800 Series Routers: <platform_name>
Determining the Software Version
To determine which version of the Cisco IOS software is currently running on your Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, or SOHO 97 router, log in to the router, and enter the show version EXEC command. The following sample output from the show version command indicates the version number on the second output line.
router> show versionCisco Internetwork Operating System SoftwareIOS (tm) C836 Software (C836-K9O3SY6-M), Version 12.3(2)XC, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1) Synched to technology version 12.3(1.6)TUpgrading to a New Software Release
For general information about upgrading to a new software release, see the Software Installation and Upgrade Procedures, which are located at http://www.cisco.com/warp/public/130/upgrade_index.shtml.
Feature Set Tables
Cisco IOS software is packaged in feature sets consisting of software images, depending on the platform. Each feature set contains a specific set of Cisco IOS features.Cisco IOS Release 12.3(2)XC3 supports the same feature sets as Cisco IOS Releases 12.3 and 12.3(2)T, but Cisco IOS Release 12.3(2)XC includes new features that are supported by the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers.
Caution
Table 2 through Table 9 list the features and feature sets that are supported in Cisco IOS Release 12.3(2)XC.
The table uses the following conventions:
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Note
New and Changed Information
The following sections list the new software features supported by the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers for Release 12.3(2)XC.
New Software Features in Release 12.3(2)XC3
The Cisco IOS Release 12.3(2)XC3 supports the same software features that are supported in the Cisco IOS Release 12.3(2)XC.
New Software Features in Release 12.3(2)XC2
The Cisco IOS Release 12.3(2)XC2 supports the same software features that are supported in the Cisco IOS Release 12.3(2)XC.
New Software Features in Release 12.3(2)XC1
The Cisco IOS Release 12.3(2)XC1 supports the same software features that are supported in the Cisco IOS Release 12.3(2)XC.
New Software Features in Release 12.3(2)XC
The following sections describe the new software features supported by the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers for Release 12.3(2)XC.
Managed LAN Switch
The Managed LAN Switch feature enables control of the four switch ports in Cisco 831, 836, and 837 routers. Each switch port is associated with a Fast Ethernet interface. The show controller fastEthernet <1-4> command output displays the status of the selected switch port.
Switch Port Support
The Managed LAN Switch feature allows setting and display of following parameters for each switch port:
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It also allows display of the link state of a switch port—that is, whether a device is connected to that port or not.
The Managed LAN Switch feature allows configuration of duplex and speed settings on the Fast Ethernet interfaces.
Table 10 lists the recommended configuration settings for duplex mode.
Table 10 Recommended Duplex Configuration Settings
Auto
Auto
Full
Full
Half
Half
Auto
Half
Table 11 lists the configuration settings that are not recommended for duplex mode.
Table 11 Duplex Configuration Settings Not Recommended
Auto
Full
Half
Full
Full
Auto
Full
Half
If the switch is connected to a non-autonegotiating device, that is not capable of autonegotiation, the switch will do the following:
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However, if the connected non-autonegotiating device can run in full-duplex mode, the following might occur:
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Although both the switch and the non-autonegotiating device can run in full-duplex mode, the switch uses a default of half-duplex mode. You might expect full duplex to be the mode used and be surprised that the throughput is less than that associated with full-duplex mode.
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If a non-autonegotiating device is running in full-duplex mode, it might attempt to transmit data at the same time that the switch is attempting to transmit data, thereby causing data collisions.
To prevent these problems, Cisco recommends that you set the duplex mode on the non-autonegotiating device to half-duplex mode.
Note
For more details on Managed LAN Switch feature, refer to the following URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123t/123t_2/mlans.htm
IP CEF and Policy-Based Routing for VoIP RTP Payload on Cisco 827-4V Router
This feature enables Cisco Express Forwarding (CEF) switching for voice traffic and policy-based routing (PBR) for locally generated voice packets. On the Cisco 827-4V router, the voice packets are currently fast switched. The existing design is such that the voice path is hardcoded to use a fast-switching path. This feature removes the hardcoded fast-switching path and modifies the existing design to allow CEF switching of voice packets.
For more details, refer to the CEF technical documentation located at the following URL:
http://www.cisco.com/en/US/tech/tk827/tk831/tk102/tech_protocol_home.html
For more details on PBR, refer to the following URL:
TACACS+
Terminal Access Controller Access Control System Plus (TACACS+) is a security application that provides centralized validation of users attempting to gain access to a router or network access server. TACACS+ services are maintained in a database on a TACACS+ daemon running, typically, on a Unix or Windows NT workstation. TACACS+ provides for separate and modular authentication, authorization, and accounting (AAA) facilities.
For more details, refer TACACS+ technical documentation located at the following URL:
http://www.cisco.com/en/US/tech/tk583/tk642/tech_technical_documentation.html
CISCO-CONFIG-MAN-MIB
The CISCO-CONFIG-MAN-MIB (Configuration Management MIB) feature provides a history of the manipulation of the configuration data. The MIB maintains data on general events, but does not keep a history of individual actions performed on either the startup config or the running config (for example, configuration commands). All the objects in this MIB are read-only; therefore, the management data cannot be modified via Simple Network Management Protocol (SNMP).
For more details on this MIB, refer to the following URL:
http://www.cisco.com/pcgi-bin/Support/Mibbrowser/mibinfo.pl?mn=CISCO-CONFIG-MAN-MIB
BGP and BGP MIB
The Border Gateway Protocol (BGP) provides loop-free interdomain routing between autonomous systems. It exchanges network information with other BGP systems by creating a TCP connection to its peers and exchanging routing updates over this connection, including information about the list of autonomous system paths. (An autonomous system [AS] is a set of routers that operate under the same administration.) This information can be used to construct a graph of autonomous system connectivity from which routing loops can be pruned and with which autonomous system-level policy decisions can be enforced. BGP is often run among the networks of Internet service providers (ISPs).
For more details, refer to the BGP technical documentation located at the following URL:
http://www.cisco.com/en/US/tech/tk365/tk80/tech_technical_documentation.html
Dial Backup over Console Port
This feature enables virtual auxiliary port capability on the Cisco 836 router console port. In this case, either asymmetric digital subscriber line (ADSL) over ISDN or ISDN interface will be the primary link, and the virtual console/auxiliary port will be the backup interface that will be connected through a modem.
Note
X.25 over ISDN Support
This feature enables the X.25 over D-channel feature on the Cisco 836 routers.
BRI is an ISDN interface, and it consists of two B-channels (B1 and B2) and one D-channel. The B-channels are used to transfer data, voice, and video. The D-channel controls the B-channels. ISDN uses the D-channel to carry signal information. This feature also enables ISDN to use D-channel in a BRI to carry X.25 packets. The D-channel has a capacity of 16 kbps, and the X.25 over D-channel can utilize up to 9.6 kbps.
X.25-over-D-Channel Logical Interface
When X.25 on ISDN is configured, a separate X.25-over-D-channel logical interface is created. You can set its parameters without disrupting the original ISDN interface configuration. The original BRI interface will continue to represent the D, B1, and B2 channels.
Because some end-user equipment uses static terminal endpoint identifiers (TEIs) to access this feature, static TEIs are supported. The dialer understands the X.25-over-D-channel calls and initiates them on a new interface.
X.25 traffic over the D channel can be used as a primary interface where low-volume, sporadic interactive traffic is the normal mode of operation. Supported traffic includes the Internet Protocol Exchange (IPX), AppleTalk, transparent bridging, Xerox Network Systems (XNS), DECnet, and IP.
This feature is not supported on the ISDN PRI.
For more details, refer to the following URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fdial_c/fnsprt3/dcdxisdn.htm
OSPF and OSPF MIB
Open Shortest Path First (OSPF) is an Interior Gateway Protocol (IGP) developed by the OSPF working group of the Internet Engineering Task Force (IETF). OSPF is a link-state routing protocol that does the following:
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Because OSPF is a link-state protocol, routers flood any change in routing information throughout the network. This action differs from that of a distance vector protocol, such as RIP, which periodically exchanges routing information only with neighboring devices.
Within an AS, each OSPF router builds and synchronizes a database of the AS network topology. The routers synchronize their databases by requesting information from other AS routers. Each router sends its information as link-state advertisements (LSAs) that include information about the state of each router and link in the AS. A link is an interface on the router. The state of the link is the description of the interface, including the router's IP address and subnet mask, and its relationship to the neighboring router.
Then, the router uses its database and the Shortest Path First (SPF) algorithm to calculate the shortest path to every destination in the AS and stores this information in a dynamic table. When changes occur, the router calculates new paths.
The router with OSPF provides the following:
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Because it is designed for IP networks, OSPF supports IP subnetting and tagging of externally derived routing information. OSPF also allows packet authentication and uses IP multicast when sending and receiving packets.
For more details, refer to the following URL:
http://www.cisco.com/warp/public/104/1.html
Class-Based Traffic Policing with CLP Tagging
When configured on the router Class-Based Traffic Policing with Cell Loss Priority (CLP) Tagging polices the flow of cells in the forward (into the network) direction of a virtual connection. The traffic policing mechanism determines whether received cells comply with the negotiated traffic management values and tag the cell with a CLP bit value of 1. The purpose of this feature is to mark traffic that does not meet the traffic management values so that packets that exceed the set values can be dropped by the network if the network is congested.
For more details on Class-Based Policing, refer to the following URL:
For more details on CLP Tagging, refer to the following URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt1/qcfcbmrk.htm
Unicast Reverse Path Forwarding
The Unicast Reverse Path Forwarding (URPF) feature helps to mitigate problems that are caused by the introduction of malformed or forged (spoofed) IP source addresses into a network by discarding IP packets that lack a verifiable IP source address. For example, a number of common types of denial-of-service (DoS) attacks, including Smurf and Tribe Flood Network (TFN), can take advantage of forged or rapidly changing source IP addresses to allow attackers to thwart efforts to locate or filter the attacks. For Internet service providers (ISPs) that provide public access, Unicast RPF deflects such attacks by forwarding only packets that have source addresses that are valid and consistent with the IP routing table. This action protects the network of the ISP, its customer, and the rest of the Internet.
For more details on how to configure URPF, refer to the following URLs:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/122sx/swcg/secure.htm#1021668
http://www.cisco.com/univercd/cc/td/doc/product/core/cis7600/122sy/cmdref/i1.htm#81185
Client-Initiated L2TP Support
Layer 2 Tunneling Protocol (L2TP) is one of the key building blocks for virtual private networks that use dial access. L2TP is endorsed by Cisco and combines the best of Cisco's Layer 2 Forwarding (L2F) protocol and Microsoft's Point-to-Point Tunneling Protocol (PPTP).
Voluntary tunneling or Client-Initiated L2TP support helps customer premises equipment to initiate L2TP sessions with the L2TP Network Servers (LNS) situated on the network. The Point-to-Point Protocol (PPP) session will be terminated on the LNS.
For more details, refer to the following URLs:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123t/123t_2/gtvoltun.htm
http://www.cisco.com/warp/public/cc/so/neso/vpn/unvpnst/2tpv3_an.htm
DNS Proxy
In virtual private network (VPN), Point-to-Point Protocol over Ethernet (PPPOE), etc. PCs connected to the LAN may get Dynamic Host Configuration Protocol (DHCP) parameters including the IP addresses of the Domain Name System (DNS) server prior to the router connecting to the WAN to get the information over IP Control Protocol (IPCP). The objective with Proxy DNS (or caching-only name server) enables the router to receive DNS queries on behalf of the real DNS servers and proxy for the hosts on the LAN connected users. This enables the DHCP server to immediately send the hosts the router's own LAN address in lieu of the DNS server's IP address. The router forwards the DNS queries from local users to real DNS servers after the WAN connection comes up and caches the DNS records in response. Over the time, cache includes the DNS information most often requested by the local resolvers and this can reduce the overhead of packets to the WAN.
The router must obtain the correct DNS server information from the WAN in order for it to function as a proxy DNS server.
The global configuration command ip dns server enables DNS proxy server functionality on the router, and causes it to forward DNS queries to the actual DNS servers. The global configuration command dns-server address causes the router to respond to DNS queries with its own IP address.
New Software Features in Release 12.3(2)T
For information regarding the features supported in Cisco IOS Release 12.3 T, refer to the Cross-Platform Release Notes and New Feature Documentation links at the following location on Cisco.com:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123relnt/xprn123/index.htm
This URL is subject to change without notice. If it changes, point your web browser to Cisco.com, and click the following path:
Service & Support: Technical Documents: Cisco IOS Software: Release 12.3: Release Notes: Cross-Platform Release Notes (Cisco IOS Release 12.3 T)
Caveats
Caveats describe unexpected behavior or defects in Cisco IOS software releases. Severity 1 caveats are the most serious caveats, severity 2 caveats are less serious, and severity 3 caveats are the least serious of these three severity levels.
Caveats in Release 12.3 T are also in Release 12.3(2)XC. For information on caveats in Cisco IOS Release 12.3 T, refer to the Caveats for Cisco IOS Release 12.3(2)T document. This document lists severity 1 and 2 caveats; the documents are located on Cisco.com.
Note
Resolved Caveats - Release 12.3(2)XC3
This section describes unexpected behavior that is fixed in Cisco IOS Release 12.3(2)XC3. Only severity level 1 through level 3 are listed.
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CBAC FTP-data sessions remain in SIS_CLOSING state.
Workaround
Lowering the inspect FTP timeout and disabling CEF will reduce exposure. Bump certain out-of-order packets to process path for catch-up and then drop packets if unsuccessful.
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CBAC inspection causes software-forced reload.
When the Cisco IOS Firewall CBAC is configured, the router may have a software-forced reload caused by one of the inspections processed. This symptom is observed when the router is part of a DMVPN hub-spoke with a Cisco VoIP phone solution deployed on it, and the router is connected to the central office over the Internet. The Cisco VoIP phone runs the SKINNY protocol.
Workaround
None.
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Corrupted OSPF Hello packets cause software-forced crash.
The router may crash on watchdog timeout while validating the OSPF Hello/DBD packets with corrupted LLS data.
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%SYS-2-MALLOCFAIL: -Process= CDP Protocol.
Memory allocation failure (MALLOCFAIL) messages may occur for a Cisco Discovery Protocol (CDP) process:
%SYS-2-MALLOCFAIL: Memory allocation of -1732547824 bytes failed from x605111F0, pool Processor, alignment 0
-Process= "CDP Protocol", ipl= 0, pid= 42
-Traceback= 602D5DF4 602D78A0 605111F8 60511078 6050EC88 6050E684 602D0E2C 602D0E18Workaround
To prevent the symptom from occurring again, disable CDP by entering the no cdp run global configuration command.
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Cisco IOS fw allows forged packets for a session initiated from inside.
A vulnerability in the TCP specification (RFC793) has been discovered by an external researcher. The successful exploitation enables an adversary to reset any established TCP connection in a much shorter time than was previously discussed publicly. Depending on the application, the connection may get automatically re-established. In other cases, a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending upon the attacked protocol, a successful attack may have additional consequences beyond terminated connection which must be considered. This attack vector is only applicable to the sessions which are terminating on a device (such as a router, switch, or computer), and not to the sessions that are only passing through the device (for example, transit traffic that is being routed by a router). In addition, the attack vector does not directly compromise data integrity or confidentiality.
All Cisco products which contain a TCP stack are susceptible to this vulnerability.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml,
and it describes this vulnerability as it applies to Cisco products that do not run Cisco IOS® software.A companion advisory that describes this vulnerability for products that run Cisco IOS software is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml.•
Bad getbuffer, crash, tag input, fragmentation.
The router may generate a "SYS-2-GETBUF" message during the "Tag Input" process and may subsequently reload unexpectedly. This symptom is observed when the router fragments a MultiProtocol Label Switching (MPLS) packet.
Workaround
None.
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NAT: Provide an API to get the pre-natted TCP Seq/Ack Numbers.
A vulnerability in the TCP specification (RFC793) has been discovered by an external researcher. The successful exploitation enables an adversary to reset any established TCP connection in a much shorter time than was previously discussed publicly. Depending on the application, the connection may get automatically re-established. In other cases, a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending upon the attacked protocol, a successful attack may have additional consequences beyond terminated connection which must be considered. This attack vector is only applicable to the sessions which are terminating on a device (such as a router, switch, or computer), and not to the sessions that are only passing through the device (for example, transit traffic that is being routed by a router). In addition, the attack vector does not directly compromise data integrity or confidentiality.
All Cisco products which contain a TCP stack are susceptible to this vulnerability.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml,
and it describes this vulnerability as it applies to Cisco products that do not run Cisco IOS® software.A companion advisory that describes this vulnerability for products that run Cisco IOS software is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml.•
Crafted packet causes reload on Cisco routers.
Routers running Cisco IOS software that supports MPLS are vulnerable to a Denial of Service (DoS) attack on MPLS disabled interfaces.
More details can be found in the security advisory which is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20050126-les.shtml•
const2:crash RIPv6_input after sending 1 packet to FF02::9 M/cast Ad.
A router that runs RIPng may crash after receiving a malformed RIPng packet, causing a DoS on the device. This symptom is observed when the ipv6 debug rip command is enabled on the router. Malformed packets can normally be sent locally. However, when the ipv6 debug rip command is enabled, the crash can also be triggered remotely. Note that RIP for IPv4 is not affected by this vulnerability.
Workaround
None.
•
Software-forced crash when router receives corrupted OSPF Hello.
A device running Cisco IOS and enabled for the OSPF Protocol is vulnerable to a DoS attack from a malformed OSPF packet. The OSPF protocol is not enabled by default.
Further details and the workarounds to mitigate the effects are explained in the Security Advisory which is available at the following URL:
http://www.cisco.com/warp/public/707/cisco-sa-20040818-ospf.shtml•
Cisco IOS may reload from specific packet.
A Cisco device reloads on receipt of a corrupt CDP packet. This symptom is observed when an empty "version" field exists in the output of the show cdp entry * command for at least one entry. One possible scenario is:
Reloading a faulty Cisco IP conference station 7935 or 7936 may cause a connected Cisco switch or router to reload. A CDP message may appear on the terminal, such as the following one:
%CDP-4-DUPLEX_MISMATCH duplex mismatch discovered on FastEthernet5/1 (not half duplex), with SEP00e0752447b2 port 1 (half duplex).
Workaround
Disable CDP by entering the no cdp run global configuration command.
First Alternate Workaround: Disable CDP on the specific (sub-)interface(s) whose corresponding neighbor(s) has or have an empty "version" field in the output of the show cdp entry * command.
Second Alternate Workaround: Disconnect the 7935 or 7936 phone, in the case of the specific symptom that is described above.
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Bus error in nat translating RSHELL packets.
A router may reload unexpectedly because of a bus error when it accesses a low address during the translation of TCP port 514. This symptom is observed on a Cisco router that runs Cisco IOS Release 12.3(5) and that is configured for Network Address Translation (NAT).
Workaround
Prevent the translation of TCP port 514.
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Undebug All stops traffic with IPsec+GRE+CEF (also see CSCeb56909).
Routers running Cisco IOS software that supports MPLS are vulnerable to a DoS attack on MPLS disabled interfaces. This is a complementary fix to CSCeb56909 which addresses this vulnerability.
More details can be found in the security advisory which is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20050126-les.shtml•
Router may crash due to corrupted data in list with Cisco IOS-firewall.
A router may reload unexpectedly after it attempts to access a low memory address. This symptom is observed after ACLs have been updated dynamically or after the router has responded dynamically to an IDS signature.
Workaround
Disable IP Inspect and IDS.
•
Malicious cfg reload neighbor routers by <show cdp entry * protocol>.
Depending upon configuration, issuing the show cdp entry * protocol command may cause a reload of the device. This symptom occurs on Cisco products that are speaking CDP with configurable interface MTU.
Workaround
Disable CDP, avoid issuing the command under given circumstances, or upgrade to a fixed version of software.
•
Multiple crafted IPv6 packets cause reload.
Cisco IOS software is vulnerable to a DoS attack from crafted IPv6 packets when the device has been configured to process IPv6 traffic. This vulnerability requires multiple crafted packets to be sent to the device which may result in a reload upon successful exploitation. More details can be found in the Security Advisory which is posted at http://www.cisco.com/warp/public/707/cisco-sa-20050126-ipv6.shtml.
•
Reload triggered in SNMP process.
Cisco IOS software release 12.3T may contain a vulnerability in processing SNMP requests which, if exploited, could cause the device to reload. The vulnerability is only present in certain Cisco IOS releases on routers and switches. This behavior was introduced via a code change and is resolved with CSCed68575. This vulnerability can be remotely triggered. A successful exploitation of this vulnerability may cause a reload of the device and could be exploited repeatedly to produce a DoS. This advisory is available at http://www.cisco.com/warp/public/707/cisco-sa-20040420-snmp.shtml
•
Modifications needed to syn rst packet response.
A vulnerability in the TCP specification (RFC793) has been discovered by an external researcher. The successful exploitation enables an adversary to reset any established TCP connection in a much shorter time than was previously discussed publicly. Depending on the application, the connection may get automatically re-established. In other cases, a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending upon the attacked protocol, a successful attack may have additional consequences beyond terminated connection which must be considered. This attack vector is only applicable to the sessions which are terminating on a device (such as a router, switch, or computer) and not to the sessions that are only passing through the device (for example, transit traffic that is being routed by a router). In addition, this attack vector does not directly compromise data integrity or confidentiality.
All Cisco products which contain TCP stack are susceptible to this vulnerability.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml,
and it describes this vulnerability as it applies to Cisco products that run Cisco IOS® software.A companion advisory that describes this vulnerability for products that do not run Cisco IOS software is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml.•
ITS/CME: aberrant data may trigger reload.
When configured for the Cisco IOS Telephony Service (ITS), Cisco CallManager Express (CME), or Survivable Remote Site Telephony (SRST), Cisco IOS release 12.3 T may contain a vulnerability in processing certain malformed control protocol messages. A successful exploitation of this vulnerability may cause a reload of the device and could be exploited repeatedly to produce a DoS.
Cisco has made free software upgrades available to address this vulnerability for all affected customers. There are workarounds available to mitigate the effects of the vulnerability. Please see the advisory available at
http://www.cisco.com/warp/public/707/cisco-sa-20050119-itscme.shtml•
BGP error msg trackback.
A device running Cisco IOS and enabled for the Border Gateway Protocol (BGP) is vulnerable to a DoS attack from a malformed BGP packet. Only devices with the command bgp log-neighbor-changes configured are vulnerable. The BGP protocol is not enabled by default, and must be configured in order to accept traffic from an explicitly defined peer. Unless the malicious traffic appears to be sourced from a configured, trusted peer, it would be difficult to inject a malformed packet.
Cisco has made free software available to address this problem. Please see the advisory available at
http://www.cisco.com/warp/public/707/cisco-sa-20050126-bgp.shtml•
Unable to telnet.
A specifically crafted TCP connection to a telnet or reverse telnet port of a device running Cisco IOS may block further telnet, reverse telnet, Remote Shell (RSH), Secure Shell (SSH), and in some cases Hypertext Transport Protocol (HTTP) access to the device. Telnet, reverse telnet, RSH and SSH sessions established prior to exploitation are not affected. All other device services will operate normally.
User-initiated, specially crafted TCP connection to a telnet or reverse telnet port results in blocking further telnet sessions, however, services such as packet forwarding, routing protocols, and all other communication to and through the device remain unaffected.
Workaround
Please see the advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040827-telnet.shtml•
IPv6 msg may cause trackback.
•
ICMPv6 pkt trackback.
•
Memory leak in CDP process with long host names.
A Cisco device experiences a memory leak in the CDP process when the device sending CDP packets sends a hostname that is 256 or more characters. There are no problems with a hostname of 255 or fewer characters.
Workaround
Configure the neighbor device to use less than a 256 character hostname, or disable the CDP process with the global command no cdp run.
•
CSCef68324 missing break statement.
Resolved Caveats - Release 12.3(2)XC2
This section describes unexpected behavior that is fixed in Cisco IOS Release 12.3(2)XC2. Only severity level 1 through level 3 are listed.
•
Adjustments of tones in accordance with Spanish and ITU-T standards.
When Phone1 goes on hook and Phone2 stays up after the conversation is over, user on Phone2 can hear the OFFHOOK_NOTICE which is not defined in ITU-T E.180 or in National Spanish standards.
Workaround
Define the custom tone table.
•
Enable ip qos dscp CLI in base images of Cisco 820 router.
•
Memory leak in Crypto IKMP.
The memory that Crypto Internet Key Management Protocol (IKMP) process holds increases. That memory is not freed and after some time may take all the memory.
Workaround
None.
•
Cisco 837 router: Middle buffers and HIFN79xx buffers issues.
A Cisco 837 router may encounter memory allocation failures in I/O memory.
Workaround
None.
•
Adding Policy-Based Routing (PBR) support for Cisco SOHO 97 router.
•
TCP checks should verify ack sequence number.
A vulnerability in the Transmission Control Protocol (TCP) specification (RFC793) has been discovered by an external researcher. The successful exploitation enables an adversary to reset any established TCP connection in a much shorter time than was previously discussed publicly. Depending on the application, the connection may get automatically re-established. In other cases, a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending upon the attacked protocol, a successful attack may have additional consequences beyond terminated connection which must be considered. This attack vector is only applicable to the sessions which are terminating on a device (such as a router, switch, or computer) and not to the sessions that are only passing through the device (for example, transit traffic that is being routed by a router). In addition, this attack vector does not directly compromise data integrity or confidentiality.
All Cisco products which contain TCP stack are susceptible to this vulnerability.
This advisory is available at http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml, and it describes this vulnerability as it applies to Cisco products that run Cisco IOS® software.
A companion advisory that describes this vulnerability for products that do not run Cisco IOS software is available at http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml.
•
TCP checks should verify syn sequence number.
A vulnerability in the Transmission Control Protocol (TCP) specification (RFC793) has been discovered by an external researcher. The successful exploitation enables an adversary to reset any established TCP connection in a much shorter time than was previously discussed publicly. Depending on the application, the connection may get automatically re-established. In other cases, a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending upon the attacked protocol, a successful attack may have additional consequences beyond terminated connection which must be considered. This attack vector is only applicable to the sessions which are terminating on a device (such as a router, switch, or computer) and not to the sessions that are only passing through the device (for example, transit traffic that is being routed by a router). In addition, this attack vector does not directly compromise data integrity or confidentiality.
All Cisco products which contain TCP stack are susceptible to this vulnerability.
This advisory is available at http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml, and it describes this vulnerability as it applies to Cisco products that run Cisco IOS® software.
A companion advisory that describes this vulnerability for products that do not run Cisco IOS software is available at http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml.
Resolved Caveats - Release 12.3(2)XC1
This section describes unexpected behavior that is fixed in Cisco IOS Release 12.3(2)XC1. Only severity level 1 through level 3 are listed.
•
Caller ID in Spain not working on all phones.
Some phones that display caller ID on the PSTN in Spain do not display caller ID on Foreign Exchnage Station (FXS) ports on the Cisco 827 router.
•
Managed Switch: Backout CSCeb45932 to go for advertisement setting.
•
Packet delay over IPSec tunnel when HW crypto used.
Workaround
Disable hardware encryption with no crypto engine accelerator command.
•
SNMP reply packets do not use the correct source address.
A SNMP request sent to the loopback interface of a Cisco router will have the wrong source address in the reply.
Workaround
Send the SNMP request to the IP address of a physical interface.
•
snmpwalk on loopbacks gets no response.
Executing an snmpwalk command on loopback interface does not yield any results.
Workaround
Execute the snmpwalk command on the physical interface.
•
Delay in processing some SNMP requests.
Some SNMP packets may stay in the input queue while being processed. However, the packets do drain on their own without any intervention from the user. This fix allows those packets to be removed from the queue more quickly.
Workaround
Protect your SNMP community strings with good password management.
Permit SNMP traffic only from trusted devices.
•
Multiple PPPoE client sessions are not created.
When multiple pppoe-client and dial-pool-number commands are configured on the interface, only one session is created after reloading the router.
Workaround
None.
•
Adjustments of tones in accordance with Spanish and ITU-T standards.
When the phone connected to FXS port of the Cisco 827-4V router goes on hook, the receiver on the otehr end can hear off hook notice. This is not defined in ITU-T E.180 or in National Spanish standards.
Workaround
Define the custom tone table.
•
MPLS-QoS: Spurious memory access occurs with MLPPPoFR and WRED.
An alignment traceback may occur when a router is configured for Multilink PPP over Frame Relay (MLPoFR) and weighted random early detection (WRED).
Workaround
Remove or modify the service-policy map to prevent WRED from running on MLPPPoFR interfaces.
Resolved Caveats - Release 12.3(2)XC
This section describes unexpected behavior that is fixed in Cisco IOS Release 12.3(2)XC. Only severity level 1 through level 3 are listed.
•
Routing loop issue with DHCP and Dynamic Multipoint VPN (DMVPN).
•
DHCP static routes are not being removed.
Workaround
After configuration change, save the configuration, and reload the router.
•
Default route learned via DHCP overrides static default route.
Workaround
Configure the command ip dhcp-client default-router distance to be the same as the statically configured route distance. This way, the DHCP learned route will overwrite the configured route but with the same information.
•
Software forced crash at "mgd_timer_first_running" related to Next Hop Resolution Protocol (NHRP).
The Cisco router running NHRP may reload due to a software forced crash.
Workaround
None.
•
Potential scalability issue with dot1x and Windows 2000 client.
•
Cannot see running configuration when Cisco Networking Services (CNS) configuration is downloaded.
Workaround
Hook-up the console.
•
When of Easy VPN client is rebooted, unknown transform error is displayed.
Workaround
Disable VPN card, or remove and re-apply the crypto map from the interface.
•
Memory leaks in NHRP and tunnel protection.
•
NHRP on multi-point generic routing encapsulation (GRE) tunnel interface causes router to crash.
Workaround
None.
•
IOS image reloads when connecting spoke to spoke.
Workaround
Disable all spoke-to-spoke connections.
•
SIP call does not go through when port 1024 is used in Via header.
Workaround
Attempt another call. Call works when port number in Via header is greater than 1024.
•
If VPN group is not cleared immediately, it leads to invalid attribute reuse.
Workaround
Wait till all the Internet Security Association and Key Management Protocol (ISAKMP) security association table is flushed and try again. The tunnel will not come up and it will show an error.
•
CNS syntax checker fails on encapsulation aal5snap command.
Workaround
Disable the syntax checker when trying to apply configuration with the encapsulation aal5snap command.
•
CNS sends keepalive values to tibgate incorrectly.
Workaround
None.
•
CNS configuration agent modifies the configuration without persisting it.
Workaround
Ensure there is no concurrent access to the router.
•
CNS configuration notify extensible markup language (XML) output needs to handle control and carriage return characters.
Workaround
None.
•
Multi-line banner command is not correctly applied by CNS configuration agent.
Workaround
None.
Open Caveats - Release 12.3(2)XC
The following sections list the open caveats for the Cisco IOS release 12.3(2)XC.
•
The Cisco 7200 series router will not perform BGP update in PPPoE with IP CEF enabled.
Workaround
Disable IP CEF on the dialer interface by using the command no ip route-cache cef.
•
PBR does not work for two policy set under route-map.
•
PPPoE client does not send PPPoE Active Discovery Terminate when clear/shutdown commands are given on dialer interface.
Related Documentation
The following sections describe the documentation available for the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers. Typically, these documents consist of hardware and software installation guides, Cisco IOS configuration and command references, system error messages, feature modules, and other documents. Documentation is available as printed manuals or electronic documents, except for feature modules, which are available online on Cisco.com.
Use these release notes with the documents listed in the following sections:
Release-Specific Documents
The following documents are specific to Release 12.3 and apply to Release 12.3(2)XC3. They are located on Cisco.com :
•
Technical Documents: Cisco IOS Software: Release 12.3: Release Notes: Cisco IOS Release 12.3 T
•
Technical Documents: Product Bulletins
•
Technical Documents: Cisco IOS Software: Release 12.3: Caveats
Note
Platform-Specific Documents
Hardware installation guides, configuration and command reference guides, and additional documents specific to the Cisco 827-4V, 828, 831, 836, 837, SOHO 91, SOHO 96, and SOHO 97 routers are available on Cisco.com at the following location:
http://www.cisco.com/univercd/cc/td/doc/product/access/acs_fix/800/index.htm
This URL is subject to change without notice. If it changes, point your web browser to Cisco.com, and click the following path:
Cisco Product Documentation: Access Servers and Access Routers: Fixed Access Routers: Cisco 800 Series Routers: <platform_name>
Obtaining Documentation
Cisco documentation and additional literature are available on Cisco.com. Cisco also provides several ways to obtain technical assistance and other technical resources. These sections explain how to obtain technical information from Cisco Systems.
Cisco.com
You can access the most current Cisco documentation at this URL:
http://www.cisco.com/univercd/home/home.htm
You can access the Cisco website at this URL:
You can access international Cisco websites at this URL:
http://www.cisco.com/public/countries_languages.shtml
Documentation DVD
Cisco documentation and additional literature are available in a Documentation DVD package, which may have shipped with your product. The Documentation DVD is updated regularly and may be more current than printed documentation. The Documentation DVD package is available as a single unit.
Registered Cisco.com users (Cisco direct customers) can order a Cisco Documentation DVD (product number DOC-DOCDVD=) from the Ordering tool or Cisco Marketplace.
Cisco Ordering tool:
http://www.cisco.com/en/US/partner/ordering/
Cisco Marketplace:
http://www.cisco.com/go/marketplace/
Ordering Documentation
You can find instructions for ordering documentation at this URL:
http://www.cisco.com/univercd/cc/td/doc/es_inpck/pdi.htm
You can order Cisco documentation in these ways:
•
http://www.cisco.com/en/US/partner/ordering/
•
Documentation Feedback
You can send comments about technical documentation to bug-doc@cisco.com.
You can submit comments by using the response card (if present) behind the front cover of your document or by writing to the following address:
Cisco Systems
Attn: Customer Document Ordering
170 West Tasman Drive
San Jose, CA 95134-9883We appreciate your comments.
Cisco Product Security Overview
Cisco provides a free online Security Vulnerability Policy portal at this URL:
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
From this site, you can perform these tasks:
•
•
•
A current list of security advisories and notices for Cisco products is available at this URL:
If you prefer to see advisories and notices as they are updated in real time, you can access a Product Security Incident Response Team Really Simple Syndication (PSIRT RSS) feed from this URL:
http://www.cisco.com/en/US/products/products_psirt_rss_feed.html
Reporting Security Problems in Cisco Products
Cisco is committed to delivering secure products. We test our products internally before we release them, and we strive to correct all vulnerabilities quickly. If you think that you might have identified a vulnerability in a Cisco product, contact PSIRT:
•
•
Tip
Never use a revoked or an expired encryption key. The correct public key to use in your correspondence with PSIRT is the one that has the most recent creation date in this public key server list:
http://pgp.mit.edu:11371/pks/lookup?search=psirt%40cisco.com&op=index&exact=on
In an emergency, you can also reach PSIRT by telephone:
•
•
Obtaining Technical Assistance
For all customers, partners, resellers, and distributors who hold valid Cisco service contracts, Cisco Technical Support provides 24-hour-a-day, award-winning technical assistance. The Cisco Technical Support Website on Cisco.com features extensive online support resources. In addition, Cisco Technical Assistance Center (TAC) engineers provide telephone support. If you do not hold a valid Cisco service contract, contact your reseller.
Cisco Technical Support Website
The Cisco Technical Support Website provides online documents and tools for troubleshooting and resolving technical issues with Cisco products and technologies. The website is available 24 hours a day, 365 days a year, at this URL:
http://www.cisco.com/techsupport
Access to all tools on the Cisco Technical Support Website requires a Cisco.com user ID and password. If you have a valid service contract but do not have a user ID or password, you can register at this URL:
http://tools.cisco.com/RPF/register/register.do
Note
Submitting a Service Request
Using the online TAC Service Request Tool is the fastest way to open S3 and S4 service requests. (S3 and S4 service requests are those in which your network is minimally impaired or for which you require product information.) After you describe your situation, the TAC Service Request Tool provides recommended solutions. If your issue is not resolved using the recommended resources, your service request is assigned to a Cisco TAC engineer. The TAC Service Request Tool is located at this URL:
http://www.cisco.com/techsupport/servicerequest
For S1 or S2 service requests or if you do not have Internet access, contact the Cisco TAC by telephone. (S1 or S2 service requests are those in which your production network is down or severely degraded.) Cisco TAC engineers are assigned immediately to S1 and S2 service requests to help keep your business operations running smoothly.
To open a service request by telephone, use one of the following numbers:
Asia-Pacific: +61 2 8446 7411 (Australia: 1 800 805 227)
EMEA: +32 2 704 55 55
USA: 1 800 553-2447For a complete list of Cisco TAC contacts, go to this URL:
http://www.cisco.com/techsupport/contacts
Definitions of Service Request Severity
To ensure that all service requests are reported in a standard format, Cisco has established severity definitions.
Severity 1 (S1)—Your network is "down," or there is a critical impact to your business operations. You and Cisco will commit all necessary resources around the clock to resolve the situation.
Severity 2 (S2)—Operation of an existing network is severely degraded, or significant aspects of your business operation are negatively affected by inadequate performance of Cisco products. You and Cisco will commit full-time resources during normal business hours to resolve the situation.
Severity 3 (S3)—Operational performance of your network is impaired, but most business operations remain functional. You and Cisco will commit resources during normal business hours to restore service to satisfactory levels.
Severity 4 (S4)—You require information or assistance with Cisco product capabilities, installation, or configuration. There is little or no effect on your business operations.
Obtaining Additional Publications and Information
Information about Cisco products, technologies, and network solutions is available from various online and printed sources.
•
http://www.cisco.com/go/marketplace/
•
•
•
http://www.cisco.com/go/iqmagazine
•
•
http://www.cisco.com/en/US/learning/index.html
This document is to be used in conjunction with the documents listed in the "Related Documentation" section.
CCSP, the Cisco Square Bridge logo, Follow Me Browsing, and StackWise are trademarks of Cisco Systems, Inc.; Changing the Way We Work, Live, Play, and Learn, and iQuick Study are service marks of Cisco Systems, Inc.; and Access Registrar, Aironet, ASIST, BPX, Catalyst, CCDA, CCDP, CCIE, CCIP, CCNA, CCNP, Cisco, the Cisco Certified Internetwork Expert logo, Cisco IOS, Cisco Press, Cisco Systems, Cisco Systems Capital, the Cisco Systems logo, Cisco Unity, Empowering the Internet Generation, Enterprise/Solver, EtherChannel, EtherFast, EtherSwitch, Fast Step, FormShare, GigaDrive, GigaStack, HomeLink, Internet Quotient, IOS, IP/TV, iQ Expertise, the iQ logo, iQ Net Readiness Scorecard, LightStream, Linksys, MeetingPlace, MGX, the Networkers logo, Networking Academy, Network Registrar, Packet, PIX, Post-Routing, Pre-Routing, ProConnect, RateMUX, ScriptShare, SlideCast, SMARTnet, StrataView Plus, SwitchProbe, TeleRouter, The Fastest Way to Increase Your Internet Quotient, TransPath, and VCO are registered trademarks of Cisco Systems, Inc. and/or its affiliates in the United States and certain other countries.
All other trademarks mentioned in this document or Website are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (0501R)
Copyright © 2005 Cisco Systems, Inc. All rights reserved.
Posted: Thu Mar 2 19:49:59 PST 2006
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