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debug ip packet

Command

Debug IP Packet

Use

This command enables IP packet debugging messages. The debugging shows all IP information being processed by the router. You can also use an access-list to limit the debug output.

Syntax

Router#debug ip packet
OR
Router#debug ip packet <access-list>

Example

debug ip packet

In the below example, we enable IP packet debugging on R2.

R2#debug ip packet
IP packet debugging is on
R2#
*Mar 1 01:06:02.083: IP: s=10.1.1.2 (local), d=224.0.0.10 (FastEthernet0/0), len 60, sending broad/multicast
*Mar 1 01:06:02.963: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.10, len 60, rcvd 2
R2#
*Mar 1 01:06:04.279: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.9, len 92, rcvd 2
R2#
*Mar 1 01:06:06.643: IP: s=10.1.1.2 (local), d=224.0.0.10 (FastEthernet0/0), len 60, sending broad/multicast
*Mar 1 01:06:07.055: IP: s=10.2.2.2 (local), d=224.0.0.5 (FastEthernet1/0), len 80, sending broad/multicast
R2#
*Mar 1 01:06:07.747: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.10, len 60, rcvd 2
*Mar 1 01:06:08.147: IP: s=10.2.2.3 (FastEthernet1/0), d=224.0.0.5, len 80, rcvd 0
R2#
*Mar 1 01:06:11.503: IP: s=10.1.1.2 (local), d=224.0.0.10 (FastEthernet0/0), len 60, sending broad/multicast
*Mar 1 01:06:12.043: IP: s=10.2.2.2 (local), d=224.0.0.9 (FastEthernet1/0), len 132, sending broad/multicast
*Mar 1 01:06:12.131: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.10, len 60, rcvd 2
R2#
*Mar 1 01:06:16.415: IP: s=10.1.1.2 (local), d=224.0.0.10 (FastEthernet0/0), len 60, sending broad/multicast
*Mar 1 01:06:16.951: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.10, len 60, rcvd 2
*Mar 1 01:06:17.059: IP: s=10.2.2.2 (local), d=224.0.0.5 (FastEthernet1/0), len 80, sending broad/multicast
R2#
*Mar 1 01:06:17.607: IP: s=2.2.2.2 (local), d=224.0.0.9 (Loopback0), len 132, sending broad/multicast
*Mar 1 01:06:17.615: IP: s=2.2.2.2 (Loopback0), d=224.0.0.9, len 132, rcvd 2
*Mar 1 01:06:18.147: IP: s=10.2.2.3 (FastEthernet1/0), d=224.0.0.5, len 80, rcvd 0
R2#
*Mar 1 01:06:21.199: IP: s=10.1.1.2 (local), d=224.0.0.10 (FastEthernet0/0), len 60, sending broad/multicast
*Mar 1 01:06:21.907: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.10, len 60, rcvd 2
R2#
*Mar 1 01:06:24.975: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:06:24.979: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:06:24.983: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:06:24.987: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:06:25.031: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:06:25.035: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:06:25.039: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:06:25.039: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:06:25.051: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:06:25.051: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:06:25.051: IP: tableid=0,
R2#s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:06:25.051: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:06:25.079: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:06:25.079: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:06:25.079: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:06:25.079: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:06:25.079: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:06:25.079: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:06:25.079: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:06:25.079: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:06:25.983: IP: s=10.1.1.2 (local), d=224.0.0.9 (FastEthernet
R2#0/0), len 72, sending broad/multicast
*Mar 1 01:06:26.163: IP: s=10.1.1.2 (local), d=224.0.0.10 (FastEthernet0/0), len 60, sending broad/multicast
*Mar 1 01:06:26.455: IP: s=10.1.1.1 (FastEthernet0/0), d=224.0.0.10, len 60, rcvd 2
*Mar 1 01:06:27.059: IP: s=10.2.2.2 (local), d=224.0.0.5 (FastEthernet1/0), len 80, sending broad/multicast
R2#un all
All possible debugging has been turned off

Here we use an access-list to filter the debug output.

R2(config)#access-list 155 permit icmp any any
R2(config)#do debug ip packet 155
IP packet debugging is on for access list 155
R2(config)#
*Mar 1 01:11:26.339: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:11:26.343: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:11:26.347: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:11:26.351: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:11:26.415: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:11:26.419: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:11:26.419: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:11:26.419: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:11:26.447: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:11:26.447: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:11:26.447: IP: tableid=0,
R2(config)#s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:11:26.447: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:11:26.447: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:11:26.447: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:11:26.447: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:11:26.447: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
*Mar 1 01:11:26.447: IP: tableid=0, s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2 (Loopback0), routed via RIB
*Mar 1 01:11:26.447: IP: s=10.1.1.1 (FastEthernet0/0), d=2.2.2.2, len 100, rcvd 4
*Mar 1 01:11:26.447: IP: tableid=0, s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), routed via FIB
*Mar 1 01:11:26.447: IP: s=2.2.2.2 (local), d=10.1.1.1 (FastEthernet0/0), len 100, sending
R2(config)#
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