Re: IPv6 fragmentation weirdness

2009-05-25 Thread JINMEI Tatuya / 神明達哉
At Thu, 14 May 2009 14:42:35 -0700, "Kevin Oberman" wrote: > I then captured the ICMP and discovered that the kernel was fragmenting > all of them! Worse, the fragment was sent out before the ICMP! What the > heck is going on! Thread synchronization? > > When I captured the packets (via tcpdump

Re: IPv6 fragmentation weirdness

2009-05-15 Thread Steve Bertrand
Steve Bertrand wrote: > Kevin Oberman wrote: > >> Second, why the heck is the fragment going out first? This should be OK, >> but I suspect many firewalls (which are often not happy with fragments) >> are not likely to pass a fragment which precedes the initial frame. > > I'll try to find some ti

Re: IPv6 fragmentation weirdness

2009-05-15 Thread Steve Bertrand
Kevin Oberman wrote: > Second, why the heck is the fragment going out first? This should be OK, > but I suspect many firewalls (which are often not happy with fragments) > are not likely to pass a fragment which precedes the initial frame. I'll try to find some time today to see if I can replicat

Re: IPv6 fragmentation weirdness

2009-05-14 Thread Bjoern A. Zeeb
On Thu, 14 May 2009, Kevin Oberman wrote: Hi, Date: Fri, 15 May 2009 00:09:02 +0200 (CEST) From: sth...@nethelp.no First, why is the kernel fragmenting this at all as it fits in the interface MTU? Good question, I definitely disagree with this behavior and would say that it breaks POLA. But

Re: IPv6 fragmentation weirdness

2009-05-14 Thread Kevin Oberman
> Date: Fri, 15 May 2009 00:09:02 +0200 (CEST) > From: sth...@nethelp.no > > > First, why is the kernel fragmenting this at all as it fits in the > > interface MTU? > > Good question, I definitely disagree with this behavior and would say > that it breaks POLA. But it's documented (see the ping6

Re: IPv6 fragmentation weirdness

2009-05-14 Thread sthaug
> First, why is the kernel fragmenting this at all as it fits in the > interface MTU? Good question, I definitely disagree with this behavior and would say that it breaks POLA. But it's documented (see the ping6 -m option). > Can anyone fetch anything from ftp.funet.fi via IPv6? I suspect it is >

IPv6 fragmentation weirdness

2009-05-14 Thread Kevin Oberman
I have recently noticed problems with data transfers via IPv6. Attempt to fetch files from dome sites was hanging as soon as the data started to flow. Felt like an MTU issue, so I tried sending various sizes of ICMP echo (ping) packets and discovered that I could not send a packet of over 1280 byte