nanog mailing list archives
Re: IP Fragmentation
From: Simon Leinen <simon.leinen () switch ch>
Date: Tue, 26 Aug 2008 23:40:17 +0200
Sam Stickland writes:
Iljitsch van Beijnum wrote:Yet all OSes have it enabled and there is no fallback to fragmentation in PMTUD: if your system doesn't get the ICMP messages, your session is dead in the water.Windows Vista/2007 has black hole detection enabled by default. It's not massively elegant, but it will keep sessions up (falls back to 536 byte MTU).
http://support.microsoft.com/kb/925280
Note that there's a new IETF specification (RFC 4821) for ("Packetization Layer") Path MTU discovery, which doesn't rely on ICMP messages to work. If what I wrote here http://kb.pert.geant2.net/PERTKB/PathMTU is correct, this has been implemented in recent (>= 2.6.17) Linux kernels. I don't know of any other OSes that have this yet - not that they'd tell me (but they could go and edit the page above, that's why it's a Wiki). -- Simon.
Current thread:
- Re: IP Fragmentation, (continued)
- Re: IP Fragmentation Glen Kent (Aug 28)
- Re: IP Fragmentation Iljitsch van Beijnum (Aug 29)
- Re: IP Fragmentation Valdis . Kletnieks (Aug 29)
- Re: IP Fragmentation Leo Bicknell (Aug 20)
- Re: IP Fragmentation Jim Shankland (Aug 20)
- Re: IP Fragmentation Valdis . Kletnieks (Aug 20)
- Re: IP Fragmentation Iljitsch van Beijnum (Aug 20)
- Re: IP Fragmentation Sam Stickland (Aug 20)
- Re: IP Fragmentation Fernando Gont (Aug 25)
- Re: IP Fragmentation Iljitsch van Beijnum (Aug 25)
- Re: IP Fragmentation Simon Leinen (Aug 26)
- Re: IP Fragmentation Iljitsch van Beijnum (Aug 20)
- RE: IP Fragmentation Tim Sanderson (Aug 20)