tcp_mtu_probing on by default?

[Ritesh Raj Sarraf]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On Tuesday 07 February 2012 04:45 AM, Martin Pool wrote:
> I have helped a few people recently who were having path MTU
> discovery problems, causing bulk TCP transfers to hang
> quasi-intermittently. Once you know the likely cause it's fairly
> easy but it's a fairly annoying problem for someone who doesn't
> recognize it.
> 
> There is a kernel sysctl "sudo sysctl -w
> net.ipv4.tcp_mtu_probing=1" that seems fairly effective at
> detecting when the problem is occurring and automatically fixing
> it.   This implements RFC 4821.  It is off by default in the
> kernel.  I haven't seen any reports of problems caused by turning
> it on, but there may be some.
> 
> I wonder if Ubuntu should turn it on in /etc/sysctl.d?


I have tried using it in the past because of my b0rken wireless router
from the ISP which had a different, non-standard, MTU size.

For me, the probing did not work at all and I had to manually set the
MTU every time I was at my home essid.


Will setting it on create trouble? Not sure. This will need testing.

- -- 
Given the large number of mailing lists I follow, I request you to CC me
in replies for quicker response
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.17 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
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=GjcM
-----END PGP SIGNATURE-----