Hi all,
Observed on 2621XM with 12.4.7 Advanced Security IOS.
Configured p-t-p GRE tunnel (path-mtu-discovery enabled) via SP network using DSL technology over the last mile.
Router receives (and accepts) ICMP unreachables 4/3 from next hop DSL router and after 'show int t0' displays very strange MTU:
...
Path MTU Discovery, ager 10 mins, min MTU 92, MTU 4294967272
...
Having this large MTU, router doesn't signal end workstations to lower path MTU below already sent 1476, causing failing of transmission of large packets.
I know the workaround, simply statically set ip mtu on tunnel interface below some value (experimentally).
Has anybody seen such strange MTU on tunnel interface, or can point BugID ?
Regards,
Adam
