126
Chapter 3
Generic Troubleshooting Tools
Precedence:
0
Type of Service:
%000
Unused: %00
Total Length: 32
Identifier: 10603
Fragmentation Flags: %000
Fragment Offset: 0
Time To Live: 1
IP Type: 0x02 IGMP
Header Checksum: 0xe6e5
Source IP Address: 172.16.10.10
Dest. IP Address: 224.0.0.4
No Internet Datagram Options
IGMP - Internet Group Management Protocol
Version: 1
Type: 3 STR# IP Protocols
Unused: 1
Checksum: 56080
Group Address:1.14.8.3
Extra bytes (Padding):
6... F..P_. %m. 36 ee d1 ee ae 46 08 00 50 9e e4 e8
20 25 6d 00
.. 00 00
Frame Check Sequence: 0x00000000
EtherPeek Sample: Cisco Proprietary Packet
Now, look at a Cisco proprietary packet. The following is a decode for a
Cisco Discovery Protocol (CDP) packet. As you can see, this is a Layer 2
packet. You can tell it is a Layer 2 packet because there is no IP or other
Layer 3 header decode. The first header section is the Ethernet 802.3 Header,
followed by the Logical Link Control (LLC) header. This header contains the
Cisco Discovery Protocol data.
Flags: 0x80 802.3
Status: 0x00
Packet Length:200
Timestamp: 14:49:03.211000 03/22/1999
802.3 Header
Destination: 01:00:0c:dd:cc:6f [0-5]
Source: 00:10:7c:75:8d:cf [6-13]
Copyright ©2000 SYBEX , Inc., Alameda, CA
www.sybex.com