> The big problem we have with POP is the Eudora users who select the
> "leave mail on server" button. How do ISPs cope with that, or do they
> lock out that option somehow?
Larger ISPs restrict the size of user mail boxes. Most users don't keep
too much email in their mail boxes, though, because it slows down their
clients. :)
> The other problem we have is that users configure their POP agents to
> poll the server at ridiculously short intervals, like every 30 seconds,
> so it is doing password checks at that rate. I guess you don't get that
> problem on dialup connections.
That's a good question. I will use a POP3 proxy that does the
authentication in the near future. Right now, it performs between 20-30
sessions (user, pass, stat, quit) per second, of which only stat and quit
are handed to the real server. If needed, DNS RR sets could increase
that number, using more machines.
Can anybody provide some data on typical POP3 request rates per user
with larger dialup installations?
While looking at performance issues: With a Pentium II running at 450
MHz, 512 MB RAM and a RAID configured as 0/1 with 6 disks, using Linux
2.0.35, I only get Exim to accept mail with a rate of up to 30-40 emails
per second. Why? I wrote a few lines C to flood a server with SMTP
requests, in case anybody is interested in profiling.
Just guessing, pre-forking Exim processes a la Apache might help to
increase that rate, but I neither have the time for profiling nor
hacking Exim.
Michael
--
*** Exim information can be found at
http://www.exim.org/ ***
