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Table Of Contents
12.2.1 Scenario 1: CTC and ONS 15454s on Same Subnet
12.2.2 Scenario 2: CTC and ONS 15454 Nodes Connected to a Router
12.2.3 Scenario 3: Using Proxy ARP to Enable an ONS 15454 Gateway
12.2.4 Scenario 4: Default Gateway on CTC Computer
12.2.5 Scenario 5: Using Static Routes to Connect to LANs
12.2.7 Scenario 7: Provisioning the ONS 15454 SOCKS Proxy Server
12.2.8 Scenario 8: Dual GNEs on a Subnet
12.2.9 Scenario 9: IP Addressing with Secure Mode Enabled
CTC Network Connectivity
This chapter provides nine scenarios showing Cisco ONS 15454s in common IP network configurations as well as information about provisionable patchcords, the routing table, external firewalls, and open gateway network element (GNE) networks. The chapter does not provide a comprehensive explanation of IP networking concepts and procedures. For IP set up instructions, refer to the "Turn Up Node" chapter of the Cisco ONS 15454 Procedure Guide.
Chapter topics include:
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Open GNE
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12.1 IP Networking Overview
ONS 15454s can be connected in many different ways within an IP environment:
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12.2 IP Addressing Scenarios
ONS 15454 IP addressing generally has eight common scenarios or configurations. Use the scenarios as building blocks for more complex network configurations. Table 12-1 provides a general list of items to check when setting up ONS 15454s in IP networks.
Note
12.2.1 Scenario 1: CTC and ONS 15454s on Same Subnet
Scenario 1 shows a basic ONS 15454 LAN configuration ( Figure 12-1). The ONS 15454s and CTC computer reside on the same subnet. All ONS 15454s connect to LAN A, and all ONS 15454s have DCC connections.
Figure 12-1 Scenario 1: CTC and ONS 15454s on Same Subnet
12.2.2 Scenario 2: CTC and ONS 15454 Nodes Connected to a Router
In Scenario 2 the CTC computer resides on a subnet (192.168.1.0) and attaches to LAN A ( Figure 12-2). The ONS 15454s reside on a different subnet (192.168.2.0) and attach to LAN B. A router connects LAN A to LAN B. The IP address of router interface A is set to LAN A (192.168.1.1), and the IP address of router interface B is set to LAN B (192.168.2.1).
On the CTC computer, the default gateway is set to router interface A. If the LAN uses DHCP (Dynamic Host Configuration Protocol), the default gateway and IP address are assigned automatically. In the Figure 12-2 example, a DHCP server is not available.
Figure 12-2 Scenario 2: CTC and ONS 15454s Connected to Router
12.2.3 Scenario 3: Using Proxy ARP to Enable an ONS 15454 Gateway
ARP matches higher-level IP addresses to the physical addresses of the destination host. It uses a lookup table (called ARP cache) to perform the translation. When the address is not found in the ARP cache, a broadcast is sent out on the network with a special format called the ARP request. If one of the machines on the network recognizes its own IP address in the request, it sends an ARP reply back to the requesting host. The reply contains the physical hardware address of the receiving host. The requesting host stores this address in its ARP cache so that all subsequent datagrams (packets) to this destination IP address can be translated to a physical address.
Proxy ARP enables one LAN-connected ONS 15454 to respond to the ARP request for ONS 15454s not connected to the LAN. (ONS 15454 proxy ARP requires no user configuration.) For this to occur, the DCC-connected ONS 15454s must reside on the same subnet. When a LAN device sends an ARP request to an ONS 15454 that is not connected to the LAN, the gateway ONS 15454 returns its MAC address to the LAN device. The LAN device then sends the datagram for the remote ONS 15454 to the MAC address of the proxy ONS 15454. The proxy ONS 15454 uses its routing table to forward the datagram to the non-LAN ONS 15454.
Scenario 3 is similar to Scenario 1, but only one ONS 15454 (#1) connects to the LAN ( Figure 12-3). Two ONS 15454s (#2 and #3) connect to ONS 15454 #1 through the SONET DCC. Because all three ONS 15454s are on the same subnet, proxy ARP enables ONS 15454 #1 to serve as a gateway for ONS 15345 #2 and #3.
Note
Figure 12-3 Scenario 3: Using Proxy ARP
You can also use proxy ARP to communicate with hosts attached to the craft Ethernet ports of DCC-connected nodes ( Figure 12-4). The node with an attached host must have a static route to the host. Static routes are propagated to all DCC peers using OSPF. The existing proxy ARP node is the gateway for additional hosts. Each node examines its routing table for routes to hosts that are not connected to the DCC network but are within the subnet. The existing proxy server replies to ARP requests for these additional hosts with the node MAC address. The existence of the host route in the routing table ensures that the IP packets addressed to the additional hosts are routed properly. Other than establishing a static route between a node and an additional host, no provisioning is necessary. The following restrictions apply:
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In Figure 12-4, Node 1 announces to Node 2 and 3 that it can reach the CTC host. Similarly, Node 3 announces that it can reach the ONS 152xx. The ONS 152xx is shown as an example; any network element can be set up as an additional host.
Figure 12-4 Scenario 3: Using Proxy ARP with Static Routing
12.2.4 Scenario 4: Default Gateway on CTC Computer
Scenario 4 is similar to Scenario 3, but Nodes 2 and 3 reside on different subnets, 192.168.2.0 and 192.168.3.0, respectively ( Figure 12-5). Node 1 and the CTC computer are on subnet 192.168.1.0. Proxy ARP is not used because the network includes different subnets. For the CTC computer to communicate with Nodes 2 and 3, Node 1 is entered as the default gateway on the CTC computer.
Figure 12-5 Scenario 4: Default Gateway on a CTC Computer
12.2.5 Scenario 5: Using Static Routes to Connect to LANs
Static routes are used for two purposes:
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In Figure 12-6, one CTC residing on subnet 192.168.1.0 connects to a router through interface A. (The router is not set up with OSPF.) ONS 15454s residing on different subnets are connected through Node 1 to the router through interface B. Because Nodes 2 and 3 are on different subnets, proxy ARP does not enable Node 1 as a gateway. To connect to the CTC computer on LAN A (subnet 192.168.1.0), you must create a static route on Node 1. You must also manually add static routes between the CTC computer on LAN A and Nodes 2 and 3 because these nodes are on different subnets.
Figure 12-6 Scenario 5: Static Route With One CTC Computer Used as a Destination
The destination and subnet mask entries control access to the ONS 15454s:
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The IP address of router interface B is entered as the next hop, and the cost (number of hops from source to destination) is 2. You must manually add static routes between the CTC computers on LAN A, B, and C and Nodes 2 and 3 because these nodes are on different subnets.
Figure 12-7 Scenario 5: Static Route With Multiple LAN Destinations
12.2.6 Scenario 6: Using OSPF
Open Shortest Path First (OSPF) is a link state Internet routing protocol. Link state protocols use a "hello protocol" to monitor their links with adjacent routers and to test the status of their links to their neighbors. Link state protocols advertise their directly connected networks and their active links. Each link state router captures the link state "advertisements" and puts them together to create a topology of the entire network or area. From this database, the router calculates a routing table by constructing a shortest path tree. Routes are recalculated when topology changes occur.
ONS 15454s use the OSPF protocol in internal ONS 15454 networks for node discovery, circuit routing, and node management. You can enable OSPF on the ONS 15454s so that the ONS 15454 topology is sent to OSPF routers on a LAN. Advertising the ONS 15454 network topology to LAN routers eliminates the need to manually enter static routes for ONS 15454 subnetworks. Figure 12-8 shows a network enabled for OSPF. Figure 12-9 shows the same network without OSPF. Static routes must be manually added to the router for CTC computers on LAN A to communicate with Nodes 2 and 3 because these nodes reside on different subnets.
OSPF divides networks into smaller regions, called areas. An area is a collection of networked end systems, routers, and transmission facilities organized by traffic patterns. Each OSPF area has a unique ID number, known as the area ID. Every OSPF network has one backbone area called "area 0." All other OSPF areas must connect to area 0.
When you enable an ONS 15454 OSPF topology for advertising to an OSPF network, you must assign an OSPF area ID in decimal format to the ONS 15454 network. Coordinate the area ID number assignment with your LAN administrator. All DCC-connected ONS 15454s should be assigned the same OSPF area ID.
Figure 12-8 Scenario 6: OSPF Enabled
Figure 12-9 Scenario 6: OSPF Not Enabled
12.2.7 Scenario 7: Provisioning the ONS 15454 SOCKS Proxy Server
The ONS 15454 SOCKS proxy is an application that allows an ONS 15454 node to serve as an internal gateway between a private enterprise network and the ONS 15454 network. (SOCKS is a standard proxy protocol for IP-based applications developed by the Internet Engineering Task Force.) Access is allowed from the private network to the ONS 15454 network, but access is denied from the ONS 15454 network to the private network. For example, you can set up a network so that field technicians and network operating center (NOC) personnel can both access the same ONS 15454s while preventing the field technicians from accessing the NOC LAN. To do this, one ONS 15454 is provisioned as a GNE and the other ONS 15454s are provisioned as ENEs. The GNE ONS 15454 tunnels connections between CTC computers and ENE ONS 15454s, providing management capability while preventing access for non-ONS 15454 management purposes.
The ONS 15454 gateway settings performs the following tasks:
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The ONS 15454 SOCKS proxy server is provisioned using the Enable SOCKS proxy server on port check box on the Provisioning > Network > General tab ( Figure 12-10). If checked, the ONS 15454 serves as a proxy for connections between CTC clients and ONS 15454s that are DCC-connected to the proxy ONS 15454. The CTC client establishes connections to DCC-connected nodes through the proxy node. The CTC client can connect to nodes that it cannot directly reach from the host on which it runs. If not selected, the node does not proxy for any CTC clients, although any established proxy connections continue until the CTC client exits. In addition, you can set the SOCKS proxy server as an ENE or a GNE:
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In addition, firewall is enabled, which means that the node prevents IP traffic from being routed between the DCC and the LAN port. The ONS 15454 can communicate with machines connected to the LAN port or connected through the DCC. However, the DCC-connected machines cannot communicate with the LAN-connected machines, and the LAN-connected machines cannot communicate with the DCC-connected machines. A CTC client using the LAN to connect to the firewall-enabled node can use the proxy capability to manage the DCC-connected nodes that would otherwise be unreachable. A CTC client connected to a DCC-connected node can only manage other DCC-connected nodes and the firewall itself.
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Figure 12-10 SOCKS Proxy Server Gateway Settings
Figure 12-11 shows an ONS 15454 SOCKS proxy server implementation. A GNE ONS 15454 is connected to a central office LAN and to ENE ONS 15454s. The central office LAN is connected to a NOC LAN, which has CTC computers. The NOC CTC computer and craft technicians must both be able to access the ONS 15454 ENEs. However, the craft technicians must be prevented from accessing or seeing the NOC or central office LANs.
In the example, the ONS 15454 GNE is assigned an IP address within the central office LAN and is physically connected to the LAN through its LAN port. ONS 15454 ENEs are assigned IP addresses that are outside the central office LAN and given private network IP addresses. If the ONS 15454 ENEs are collocated, the craft LAN ports could be connected to a hub. However, the hub should have no other network connections.
Figure 12-11 Scenario 7: ONS 15454 SOCKS Proxy Server with GNE and ENEs on the Same Subnet
Table 12-2 shows recommended settings for ONS 15454 GNEs and ENEs in the configuration shown in Figure 12-11.
Figure 12-12 shows the same SOCKS proxy server implementation with ONS 15454 ENEs on different subnets. Figure 12-13 shows the implementation with ONS 15454 ENEs in multiple rings. In each example, ONS 15454 GNEs and ENEs are provisioned with the settings shown in Table 12-2.
Figure 12-12 Scenario 7: ONS 15454 SOCKS Proxy Server with GNE and ENEs on Different Subnets
Figure 12-13 Scenario 7: ONS 15454 SOCKS Proxy Server With ENEs on Multiple Rings
Table 12-3 shows the rules the ONS 15454 follows to filter packets for the firewall when nodes are configured as ENEs and GNEs.
If the packet is addressed to the ONS 15454, additional rules, shown in Table 12-4, are applied. Rejected packets are silently discarded.
Table 12-4 SOCKS Proxy Server Firewall Filtering Rules When Packet Addressed to ONS 15454
TCC2/TCC2P Ethernet interface
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DCC interface
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1 UDP = User Datagram Protocol
2 TCP = Transmission Control Protocol
3 ICMP = Internet Control Message Protocol
If you implement the SOCKS proxy server, note that all DCC-connected ONS 15454s on the same Ethernet segment must have the same gateway setting. Mixed values produce unpredictable results, and might leave some nodes unreachable through the shared Ethernet segment.
If nodes become unreachable, correct the setting by performing one of the following:
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12.2.8 Scenario 8: Dual GNEs on a Subnet
The ONS 15454 provides GNE load balancing, which allows CTC to reach ENEs over multiple GNEs without the ENEs being advertised over OSPF. This feature allows a network to quickly recover from the loss of GNE, even if the GNE is on a different subnet. If a GNE fails, all connections through that GNE fail. CTC disconnects from the failed GNE and from all ENEs for which the GNE was a proxy, and then reconnects through the remaining GNEs. GNE load balancing reduces the dependency on the launch GNE and DCC bandwidth, both of which enhance CTC performance. Figure 12-14 shows a network with dual GNEs on the same subnet.
Figure 12-14 Scenario 8: Dual GNEs on the Same Subnet
Figure 12-15 shows a network with dual GNEs on different subnets.
Figure 12-15 Scenario 9: Dual GNEs on Different Subnets
12.2.9 Scenario 9: IP Addressing with Secure Mode Enabled
TCC2/TCC2P cards provide a secure mode option allowing you to provision two IP addresses for the ONS 15454. One IP address is provisioned for the ONS 15454 backplane LAN port. The other IP address is provisioned for the TCC2/TCC2P TCP/IP craft port. The two IP addresses provide an additional layer of separation between the craft access port and the ONS 15454 LAN. If secure mode is enabled, the IP addresses provisioned for the TCC2/TCC2P TCP/IP ports must follow general IP addressing guidelines. In addition, TCC2/TCC2P IP addresses must reside on a different subnet from the ONS 15454 backplane port and ONS 15454 default router IP addresses.
The IP address assigned to the backplane LAN port becomes a private address, which is used to connect the ONS 15454 GNE to an OSS (Operations Support System) through a central office LAN or private enterprise network. In secure mode, the backplane's LAN IP address is not displayed on the CTC node view or to a technician directly connected to the node by default. This default can be changed to allow the backplane IP address to be viewed on CTC only by a Superuser.
Figure 12-16 shows an example of ONS 15454s on the same subnet with secure mode enabled.
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Figure 12-16 Scenario 9: ONS 15454 GNE and ENEs on the Same Subnet with Secure Mode Enabled
Figure 12-17 shows an example of ONS 15454s connected to a router with secure mode enabled. In each example, TCC2/TCC2P port addresses are on a different subnet from the node backplane addresses
Figure 12-17 Scenario 9: ONS 15454 GNE and ENEs on Different Subnets with Secure Mode Enabled
12.3 Provisionable Patchcords
A provisionable patchcord is a user-provisioned link that is advertised by OSPF throughout the network. Provisionable patchcords, also called virtual links, are needed in the following situations:
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Provisionable patchcords are required on both ends of a physical link. The provisioning at each end includes a local patchcord ID, slot/port information, remote IP address, and remote patchcord ID. Patchcords appear as dashed lines in CTC network view.
Table 12-5 lists the supported card combinations for client and trunk ports in a provisionable patchcord.
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Table 12-6 lists the supported card combinations for client-to-client ports in a patchcord.
Table 12-7 lists the supported card combinations for trunk-to-trunk ports in a patchcord.
Optical ports have the following requirements when used in a provisionable patchcord:
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Transponder and muxponder ports have the following requirements when used in a provisionable patchcord:
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DWDM cards support provisionable patchcords only on optical channel ports. Each DWDM optical channel port can have only one provisionable patchcord.
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12.4 Routing Table
ONS 15454 routing information is displayed on the Maintenance > Routing Table tabs. The routing table provides the following information:
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Table 12-8 shows sample routing entries for an ONS 15454.
Entry 1 shows the following:
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Entry 2 shows the following:
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Entry 3 shows the following:
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Entry 4 shows the following:
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Entry 5 shows a DCC-connected node that is accessible through a node that is not directly connected:
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12.5 External Firewalls
This section provides sample access control lists for external firewalls. Table 12-9 lists the ports that are used by the TCC2/TCC2P card.
Table 12-9 Ports Used by the TCC2/TCC2P
0
Never used
D
20
FTP
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21
FTP control
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22
SSH
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23
Telnet
D
80
HTTP
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111
SUNRPC
NA
161
SNMP traps destinations
D
162
SNMP traps destinations
D
513
rlogin
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683
CORBA IIOP
OK
1080
Proxy server (socks)
D
2001-2017
I/O card Telnet
D
2018
DCC processor on active TCC2/TCC2P
D
2361
TL1
D
3082
Raw TL1
D
3083
TL1
D
5001
BLSR server port
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5002
BLSR client port
D
7200
SNMP alarm input port
D
9100
EQM port
D
9401
TCC boot port
D
9999
Flash manager
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10240-12287
Proxy client
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57790
Default TCC listener port
OK
1 D = deny, NA = not applicable, OK = do not deny
The following access control list (ACL)example shows a firewall configuration when the SOCKS proxy server gateway setting is not enabled. In the example, the CTC workstation's address is 192.168.10.10. and the ONS 15454 address is 10.10.10.100. The firewall is attached to the GNE, so inbound is CTC to the GNE and outbound is from the GNE to CTC. The CTC Common Object Request Broker Architecture (CORBA) Standard constant is 683 and the TCC CORBA Default is TCC Fixed (57790).
access-list 100 remark *** Inbound ACL, CTC -> NE ***access-list 100 remarkaccess-list 100 permit tcp host 192.168.10.10 host 10.10.10.100 eq wwwaccess-list 100 remark *** allows initial contact with ONS 15454 using http (port 80) ***access-list 100 remarkaccess-list 100 permit tcp host 192.168.10.10 host 10.10.10.100 eq 57790access-list 100 remark *** allows CTC communication with ONS 15454 GNE (port 57790) ***access-list 100 remarkaccess-list 100 permit tcp host 192.168.10.10 host 10.10.10.100 establishedaccess-list 100 remark *** allows ACKs back from CTC to ONS 15454 GNE ***access-list 101 remark *** Outbound ACL, NE -> CTC ***access-list 101 remarkaccess-list 101 permit tcp host 10.10.10.100 host 192.168.10.10 eq 683access-list 101 remark *** allows alarms etc., from the 15454 (random port) to the CTC workstation (port 683) ***access-list 100 remarkaccess-list 101 permit tcp host 10.10.10.100 host 192.168.10.10 establishedaccess-list 101 remark *** allows ACKs from the 15454 GNE to CTC ***The following ACL (access control list) example shows a firewall configuration when the SOCKS proxy server gateway setting is enabled. As with the first example, the CTC workstation address is 192.168.10.10 and the ONS 15454 address is 10.10.10.100. The firewall is attached to the GNE, so inbound is CTC to the GNE and outbound is from the GNE to CTC. CTC CORBA Standard constant (683) and TCC CORBA Default is TCC Fixed (57790).
access-list 100 remark *** Inbound ACL, CTC -> NE ***access-list 100 remarkaccess-list 100 permit tcp host 192.168.10.10 host 10.10.10.100 eq wwwaccess-list 100 remark *** allows initial contact with the 15454 using http (port 80) ***access-list 100 remarkaccess-list 100 permit tcp host 192.168.10.10 host 10.10.10.100 eq 1080access-list 100 remark *** allows CTC communication with the 15454 GNE (port 1080) ***access-list 100 remarkaccess-list 101 remark *** Outbound ACL, NE -> CTC ***access-list 101 remarkaccess-list 101 permit tcp host 10.10.10.100 host 192.168.10.10 establishedaccess-list 101 remark *** allows ACKs from the 15454 GNE to CTC ***12.6 Open GNE
The ONS 15454 can communicate with non-ONS nodes that do not support point-to-point protocol (PPP) vendor extensions or OSPF type 10 opaque link-state advertisements (LSA), both of which are necessary for automatic node and link discovery. An open GNE configuration allows the DCC-based network to function as an IP network for non-ONS nodes.
To configure an open GNE network, you can provision SDCC, LDCC, and GCC terminations to include a far-end, non-ONS node using either the default IP address of 0.0.0.0 or a specified IP address. You provision a far-end, non-ONS node by checking the "Far End is Foreign" check box during SDCC, LDCC, and GCC creation. The default 0.0.0.0 IP address allows the far-end, non-ONS node to provide the IP address; if you set an IP address other than 0.0.0.0, a link is established only if the far-end node identifies itself with that IP address, providing an extra level of security.
By default, the SOCKS proxy server only allows connections to discovered ONS peers and the firewall blocks all IP traffic between the DCC network and LAN. You can, however, provision proxy tunnels to allow up to 12 additional destinations for SOCKS version 5 connections to non-ONS nodes. You can also provision firewall tunnels to allow up to 12 additional destinations for direct IP connectivity between the DCC network and LAN. Proxy and firewall tunnels include both a source and destination subnet. The connection must originate within the source subnet and terminate within the destination subnet before either the SOCKS connection or IP packet flow is allowed.
To set up proxy and firewall subnets in CTC, use the Provisioning > Network > Proxy and Firewalls subtabs. The availability of proxy and/or firewall tunnels depends on the network access settings of the node:
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Figure 12-18 shows an example of a foreign node connected to the DCC network. Proxy and firewall tunnels are useful in this example because the GNE would otherwise block IP access between the PC and the foreign node.
Figure 12-18 Proxy and Firewall Tunnels for Foreign Terminations
Figure 12-19 shows a remote node connected to an ENE Ethernet port. Proxy and firewall tunnels are useful in this example because the GNE would otherwise block IP access between the PC and foreign node. This configuration also requires a firewall tunnel on the ENE.
Figure 12-19 Foreign Node Connection to an ENE Ethernet Port
Posted: Tue Nov 27 06:13:45 PST 2007
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