After about a max of 70-80 inbound connections(sometimes less, sometimes more)
ime, that's a very large number of inbound connections for legit senders (but not large for an attack).
If you are not being attacked, then I'd say you need to look at why 70 SMTPD connections need to be open. The 70 might be a symptom of a problem or bad design elsewhere rather than the real problem.
1. wan (or other) link is congested and all TCP connections are taking a much longer time.
2. IMail disk file i/o is congested, esp the Imail/spool/ dir, where SMTPD writes the in-bound mail to the queue.
re connections are allowed, not even using telnet to port 25 (see below).
As I said last week, it's very easy for IMGate to deliver so much mail to Imail that Imail does refuse any more TCP connections (connection refused).
number of SMTP connections, but with the number of processes, processing mail already received. Which is it?
Scott and Sandy say on SMTPD instance handles all connections from STMP clients.
testing, the CPU's are typically 25% loaded, with plenty of actual Memory remaining, and the Virtual memory never increasing.
but you don't tell us the critical factor in any mailserver, the disk i/o situation, your partitioning scheme, your level of disk frag.
When we put a UNIX server in front of our mail server, a much slower machine, less memory, it will receive more mail that Imail can, and Imail cannot keep up with the mail being relayed.
... which is how many msgs/hour in peak hours? I know one IMGate machine that is receiving 20+ K messags/hour over 24 hours, meaning the peak hours are probably a lot higher.
In IMGate, we see the transit "lifetime" msg through IMGate to Imail taking well under 5 seconds average, somemtimes 1 or 2 seconds.
Note that the lifetime is from the time the msg is received to disk by IMGate, then the msg is picked up, Imail is called, and the msgs is delivered to Imail, and IMGate deletes the msg from disk.
Len
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