Cisco Cisco IOS Software Release 12.0(22)S

To display IP multicast packets received and sent, use the debug ip mpacket privileged EXEC 
command. To disable the debugging output, use the no form of this command.

debug ip mpacket [detail | fastswitch] [access-list] [group]

no debug ip mpacket [detail | fastswitch] [access-list] [group]

Displays all IP multicast packets switched at the process level.

Privileged EXEC

This command displays information for multicast IP packets that are forwarded from this router. By 
using the access-list or group argument, you can limit the display to multicast packets from sources 
described by the access list or a specific multicast group.

Use this command with the debug ip packet command to display additional packet information.

The debug ip mpacket command generates many messages. Use this command with care so that 
performance on the network is not affected by the debug message traffic.

The following is sample output from the debug ip mpacket command:

Router# debug ip mpacket 224.2.0.1 

IP: s=10.188.34.54 (Ethernet1), d=224.2.0.1 (Tunnel0), len 88, mforward 

IP: s=10.188.34.54 (Ethernet1), d=224.2.0.1 (Tunnel0), len 88, mforward 

IP: s=10.188.34.54 (Ethernet1), d=224.2.0.1 (Tunnel0), len 88, mforward 

IP: s=10.162.3.27 (Ethernet1), d=224.2.0.1 (Tunnel0), len 68, mforward 

(Optional) Causes the debug ip mpacket command to display IP 
header information and MAC address information.

(Optional) Displays IP packet information in the fast path.

(Optional) Access list number.

(Optional) Group name or address.

10.2

This command was introduced.

12.1(2)T

The fastswitch keyword was added.

12.0(18)ST

This command was integrated into Cisco IOS Release 12.0(18)ST.

12.0(22)S

This command was integrated into Cisco IOS Release 12.0(22)S.