>> 	i guess udp pcb is keep pointing to MTU=1500 route (like default)
>> 	somehow.  normally udp pcb will get notified from icmp layer using
>> 	*ctlinput, and should point to MTU=1280 route.
>
>I think you are right. In my setup sending of large udp packets on bones
>is done by bind9. When there is a host route with mtu 1280 and I restart
>bind9, packets are sent with max 1280 size.
>
>So, it looks like those sockets that were present before the host route
>are not informed by a mtu change.
>
>This is reproducable now:
>- delete host route
>- start named
>- send dns query 
>- dns reply is sent with > 1280, no action on icmp6 packet too big
>(host route is present)
>- send dns query 
>- dns reply is sent with > 1280, no action on icmp6 packet too big
>- restart named
>- send dns query
>- dns reply with <= 1280, OK

	hmm.  do you see anything weird on netstat -sn?  i guess you have
	something weird in icmp6 section.

itojun