Caching learned MSS/MTU values
Hannes Frederic Sowa
hannes at stressinduktion.org
Fri Oct 18 18:45:43 CEST 2013
On Fri, Oct 18, 2013 at 04:35:39PM +0000, Templin, Fred L wrote:
> > There is basis support for mtu probing for tcp. It is currently
> > deactivated by
> > default: cat /proc/sys/net/ipv4/tcp_mtu_probing => 0
> > Guess it had not the seen the testing it needs to activate it by
> > default.
> Yes, I had heard that there was an off-by-default linux implementation
> of RFC4821. I also heard that it was not yet fully compliant to the
> spec, but that was a while ago now and it may have gotten better by now?
Going through the git logs it does not seem to get a lot of commits. Maybe it
is just stable, I don't know. I'll activate it on my boxes now to see if
The committed patch droped the note that it is not fully spec compliant but
seems to be based on the -05 draft.
> > I still have to take a closer look at SEAL. Thanks for the reminder. ;)
> Sure. I have recently published an alpha linux implementation of SEAL:
> It is still in early phases and does not yet fully implement the spec
> but does implement the core RFC4821 path MTU probing and fragmentation
> requirements for several different varieties of tunnels. The code is
> also quite ugly, and I would welcome any help on cleaning it up and/or
> implementing more features in the spec.
Oh, that is interesting. I'll have a look at the weekend.
More information about the ipv6-ops