Debian – Exim4 slow connection and transaction time

debianeximsmtp

I've setup my email server and have run some tests from mxtoolbox.com Everything is working properly but the only issue I have is a slow connection and transaction time.

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What could this be caused by as I've tried to troubleshoot but without success.

Best Answer

Many things could result in delays. I'm afraid I'm not familiar with mxtoolbox.com. I assume you have access to a command line?

A misconfigured Exim feature might be trying to verify something about the sender/message and exim processes the message only after the feature times out. Here are some of the things I've run into:

  1. Name resolution issues. Solution: update "resolv.conf" with working DNS servers (try 8.8.8.8)
  2. ipv6 issues. Solution: disable ipv6
  3. Virus/Spam checking: Try disabling it
  4. RFC1413 issues: try rfc1413_query_timeout = 2s or rfc1413_query_timeout = 0 which turns off the check entirely

You could also try running exim -v or exim -d and watch the debugging output to view what exim is doing when it hangs. This article might help.

Good luck

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