I am trying to verify the TTL info and understand why a 184.108.40.206 - "All Routers on local subnet" multicast ( the HSRP packets ) have a TTL of 2, seems weird to me as they shouldn't be capable of being 'routed' off the local subnet, please correct me. I have created a HSRP pair using 2 of our 2620's in our test rig and also see a TTL of 2, so expect that thats how it works.
Is this correct ?
The issue is currently in the hands of Netscreen as their 208 firewall (new model that problem seem particular to) appears to be taking in the hsrp packet, changing the source MAC to its own and dest MAC to that of the cisco virtual MAC and then pushing the packet back out of the same interface, again seems very wrong to me... The result of which is that the cisco 7200's cry foul and log a duplicate IP message as the packet source IP is still the same as when the cisco originally sent the packet out.
I've never looked at HSRP packets TTL values, but I think routers set TTL to 2 in order to avoid that upon receiving they have to send a ICMP TTL exceeded message, which might happen if TTL was set to 1. If a router receives an IP packet with TTL=1, it will decrement the TTL field which result TTL=0, which normally causes the router to send an ICMP TTL exceeded message to the source of the packet.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...