dropping UDP packets in openconnect VPN

[er0ck]

i'm a user, not an admin. i don't have shell access to the afs
servers, don't think i can run tcpdump on that end.

however, this is silly, but it looks like reducing the MTU has made
afs MUCH more snappy.
the vpn server was giving me an MTU of 1602.  my gig ethernet sans
jumbo frames is set to 1500.  1602 seems pretty big.
i asked another user what his MTU was set to on AT&T client 1362.  i
used that and it seems snappy.

any advice on theory of how to optimize this?

thanks again for all your help.
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On Wed, Aug 17, 2011 at 12:13, David Woodhouse <dwmw2 at infradead.org> wrote:
> On Wed, 2011-08-17 at 11:49 -0700, er0ck wrote:
>>
>> plain old traceroutes to the afs servers work just fine.  so i'm back
>> to square-one trying to figure out why afs is so slow.
>> thanks for your attempts to help David, this appears to be an afs problem.
>> i'll have to sit down and do some benchmarking on the vpn in general
>> and compare to afs.
>
> Run tcpdump on both ends and compare. Perhaps there is some systematic
> packet loss? I know little of RxRPC; what happens if full-sized packets
> are lost? Does it wait a while and then send smaller ones? Is that
> consistent with what you're seeing?
>
> Try reducing the MTU on your tun0 device?
>
> --
> dwmw2
>
>