Sahil Tandon:
> This afternoon a user complained about missing email and mentioned that
> the sender "is not getting a bounce". In the logs I see several
> iterations of:
>
> Oct 10 09:51:42 aegis postfix/smtpd[52803]: timeout after DATA (256605 bytes)
> from relay.airtiger.com[63.170.171.120]
> Oct 10 10:09:56 aegis postfix/smtpd[53022]: timeout after DATA (3240605
> bytes) from relay.airtiger.com[63.170.171.120]
> Oct 10 11:09:36 aegis postfix/smtpd[53463]: timeout after DATA (2998025
> bytes) from relay.airtiger.com[63.170.171.120]
>
If the last two are really hourly retransmissions, then their
inbound bitrate is very low (ball-park 100kbit/second).
> HOST: aegis.hamla.org Loss% Snt Last Avg Best Wrst StDev
> 1. bfw02.m5hosting.com 0.0% 10 2.4 1.8 0.5 3.7 1.1
> 2. br02.sdtc.m5hosting.net 0.0% 10 2.5 55.4 2.3 528.5 166.2
> 3. ais-ar01.sdtc.m5hosting.net 0.0% 10 0.8 16.6 0.5 118.7 36.9
> 4. owb.br03.g5-1.americanis.net 0.0% 10 4.7 4.7 4.6 4.9 0.1
> 5. 207.43.189.209 0.0% 10 69.0 35.3 4.7 101.0 40.4
> 6. sl-crs2-ana-0-13-3-0.sprintl 0.0% 10 5.7 5.5 5.3 5.8 0.1
> 7. sl-crs2-ana-0-8-0-0.sprintli 0.0% 10 5.3 5.4 5.3 5.5 0.1
> 8. sl-gw9-ana-4-0-0.sprintlink. 0.0% 10 218.1 26.8 5.3 218.1 67.2
> 9. sl-airti-5-0.sprintlink.net 0.0% 10 13.4 13.5 12.9 14.8 0.5
> 10. ??? 100.0 10 0.0 0.0 0.0 0.0 0.0
According my own mtr results, there's a 9ms increase in latency at
sl-airti-5-0.sprintlink.net, which suggests they have a low-bandwidth
network connection.
That is not necessarily bad - my primary connection is slow, too.
But I have experienced trouble sending large email files over slow
connections when equipment isn't working error-free and TCP just
gives up.
Running tcpdump will show if there are lots of retransmissions,
which I expect there to be. Maybe you can tune your end to try
longer.
Wietse
