> On Fri, Jun 04, 2004 at 20:15:51 +0900, Jun-ichiro itojun Hagino wrote:
> 
> > > Anything else I could try to pinpoint this?
> > 
> > 	try monitoring how it works with netstat -rn, netstat -sn and tcpdump,
> > 	and compare them... (yes, it's painful i guess)
> 
> The problem only seems to happen with sendto().
> 
> I use the attached program. This is what I do:
> - delete the host route
> - start tcpdump in xterm 1
> - start the program in xterm 2

	with sendto() (without connnect()) on udp, udp6_ctlinput passes 0
	as the last argument to icmp6_mtudisc_update().  in that case, unless
	you have tons of (> 256) routing entries created PMTUD, path MTU
	discovery should work.

itojun