I have a PHP web app which is using SMTP to sendmail on
localhost to send email.
I would like sendmail to accept the mail request immediately and queue it for later sending, as I don't want to have user-facing request threads blocked on emails.
Sendmail is installed with the default settings on RHEL web servers.
sendmail is blocking for a long time after the
I have looked in the sendmail logs, and there are plenty of "deferred" emails, but nothing which looks responsible for this delay.
- How can I diagnose what is slowing down
- How can I configure
sendmailto always accept the mail immediately and to queue the mail for later sending?
Update: I'm not sure, but it looks like this might be linked to
aol.com addresses. I strongly suspect that
sendmail is doing some kind of blocking receipient address verification at the accept-email-for-sending stage. How can I disable that, so that
sendmail doesn't block my UI threads?
Update 2: This only seems to happen at busy times. Perhaps I am running out of
sendmail threads or something? How can I check that?