Time to live exceeded for a specific ip only

[abhijit_roy]

Hi All, 

Please help me to find out exact root cause of following case

I have recently install X440G2-48p-10G4 in our network with ExtremeXOS version 31.1.1.3 31.1.1.3-patch1-1 by release-manager, in fact all of our old switches are same model, configuration of each switch as follows,

1. One super vlan with 3 sub vlan and ip forwarding is enabled, there was no problem as such till date but when we have installed the new switch of same model just few days back a typical problem started, all ip’s of of one sub vlan range working perfectly except one, the ip is 10.91.95.7, when i ping this ip from a p.c it is saying Time to live exceeded, where as all ip’s on same sub-vlan’s ip range working perfectly and users are facing no issue, the sub vlan address range is 10.91.95.1-10.91.95.254.
2. When I do tracerout that ip from switch it is going to other switches vsuper ip on the network, in which that 10.91.95.7 series ip not exist at all, ideally that traceroute should indicate same switch vsuper ip which is 10.91.1.203, but it is showing some wrong ip’s of other switch, when i do show iproute following is the output, in which bold one is wrong, when i reboot the switch following bold line gone but error still exist when i ping this 10.91.95.7 ip it is saying  Time to live exceeded in reply where as this ip is  not exist in any p.c/device in my entire network.

Ori  Destination        Gateway         Mtr  Flags         VLAN       Duration
#s   Default Route      10.91.1.250     1    UG---S-um--f- vsuper     0d:21h:20m:28s
#d   10.91.0.0/16       10.91.1.203     1    U------um--f- vsuper     0d:21h:20m:30s
#i   10.91.95.7/32      10.91.95.7      1    UG-----um--f- vsuper     0d:0h:5m:0s

10.91.1.250 is our main gateway of all switches which is provided by different dept and all of our switch uplink terminate on that switch.

PLEASE HELP ME FIND OUT EXACT ISSUE

[Tomasz · Accepted solution]

Hi,

I think some more details on the network design might be helpful.

Under ‘show iproute’ #i says the route appeared in the routing table as due to ICMP Redirect. This must’ve been sent from some adjacent router. You could try to block ICMP with ACLs for instance and see if the routing table keeps off that single entry. If then you have TTL exceeded, that suggests packet dying when hopping between routers (could happen with static routing being misconfigured for example). I’d go for some thorough packet capture filtering for a packet that dies to see what’s going on.

https://extremeportal.force.com/ExtrArticleDetail?an=000082238

Hope that helps,

Tomasz

P.S. Try ‘disable icmp useredirects’, the ACL is an overkill here. Just found such command.

[Stefan_K_]

This is a community forum and we are only here in our free-time as a hobby. If you want fast and professional support, you should get in contact with ExtremeNetworks support (GTAC)

[abhijit_roy]

STILL THERE IS NO RESPONSE FROM ANYONE???

[abhijit_roy]

Anybody have any answer????