04-25-2015 06:59 PM - edited 03-05-2019 01:20 AM
Hi All
The following is ip packet debug output. I know 224.0.0.10, but where does 224.0.0.2 come from ? why do the len is 48 instead of 60 ? Thank you
R3(config-if)#
*Mar 1 00:47:46.551: IP: s=3.1.1.4 (Vlan3), d=224.0.0.10, len 60, rcvd 2
*Mar 1 00:47:46.687: IP: s=3.1.1.2 (Vlan3), d=224.0.0.10, len 60, rcvd 2
*Mar 1 00:47:47.111: IP: s=4.1.1.3 (local), d=224.0.0.10 (Vlan4), len 60, sending broad/multicast
*Mar 1 00:47:47.183: IP: s=3.1.1.3 (local), d=224.0.0.2 (Vlan3), len 48, sending broad/multicast
*Mar 1 00:47:47.487: IP: s=3.1.1.4 (Vlan3), d=224.0.0.2, len 48, rcvd 0
R3(config-if)#
*Mar 1 00:47:49.651: IP: s=3.1.1.3 (local), d=224.0.0.10 (Vlan3), len 60, sending broad/multicast
*Mar 1 00:47:50.183: IP: s=3.1.1.3 (local), d=224.0.0.2 (Vlan3), len 48, sending broad/multicast
*Mar 1 00:47:50.515: IP: s=3.1.1.4 (Vlan3), d=224.0.0.2, len 48, rcvd 0
Solved! Go to Solution.
04-25-2015 07:20 PM
Hello showipinterface,
224.0.0.2 is the all routers multicast address, which is used for the HSRP hello packets.
Here is a link that has info for HSRP.
http://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9281-3.html
Hope this helps.
04-26-2015 03:49 AM
Correct but there are other protocols using that address: IGMP and LDP at least, but I suppose many other.
04-25-2015 07:20 PM
Hello showipinterface,
224.0.0.2 is the all routers multicast address, which is used for the HSRP hello packets.
Here is a link that has info for HSRP.
http://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9281-3.html
Hope this helps.
04-26-2015 03:49 AM
Correct but there are other protocols using that address: IGMP and LDP at least, but I suppose many other.
04-26-2015 08:50 AM
Very true. I should have added that other protocols use 224.0.0.2 as well.
I was basing it on a previous posting showip had made that showed HSRP was configured in his network.
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