On Friday (17th Jan) we noticed that the main incoming exim mail relay
at Imperial started to reject connections - well what actually happened
was that the connection was made but we never got the smtp transactions
starting.
After a while I rebuild exim, increasing the number of SMTP listens from 5
to 20. This kind of solved the problem, it still happened, but much less
often. With this number of listens it also became clear what was going
on - lots of connections where hanging in SYS_RECV state. Tracerouting
those connections pointed them all to a part of the US backbone that was
having routing problems.
It may be a good idea to increasing the number of listens from 5. I agree
that this cannot solve such a problem in all cases, but it certainly seemed
to help a lot in this case.
Views anybody?
Martyn
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| Martyn Hampson | Tel: 0171 594 6973 |
| Imperial College | Fax: 0171 594 6958 |
| Computer Centre | E-Mail: M.Hampson@??? |
| London SW7 2BP, ENGLAND | "Don't just do something, sit there!" |
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