IPv6 TCP transfers are hanging

JINMEI Tatuya /神明達哉 jinmei at isl.rdc.toshiba.co.jp
Tue Jan 11 19:30:58 PST 2005

>>>>> On Tue, 11 Jan 2005 14:01:29 -0800, 
>>>>> "Kevin Oberman" <oberman at es.net> said:

> I think I have found a problem with TCP when run over IPv6.
> I set my MSS for TCP to 1460 to allow a full 1500 byte MTU to be
> utilized on my systems. (Yes, I see that this does break some things
> like communicating via links where PMTUD is blocked and one or more
> links restrict MTU to some size less than 1500 bytes.

> What I am specifically seeing is a packet being sent out with a TCP
> length of 1460. While this is fine for IPv4, it's too back for IPv6 and,
> as you might expect, the far end never receives this packet.

Two questions to clarify things:

1. Which version of FreeBSD are you using?
2. How did you set the MSS?

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					jinmei at isl.rdc.toshiba.co.jp

More information about the freebsd-net mailing list