Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My sendmail server occasionally fails at delivering an email. I get a Service unavailable error:

Feb  7 23:45:01 ip-10-101-xx-xx sm-mta[3838]: q17Nj0RQ003836: to=<>, ctladdr=<www-data@ip-xxxxx.ec2.internal> (33/33), delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=121203, [144.92.xx.xx], dsn=5.0.0, stat=Service unavailable

My question is how can I tell if the service at my end was down or the service at the recipient? If it's my problem, how can I solve it?

I'm asking because I'm getting a lot of these errors lately...

share|improve this question

migrated from Feb 22 '12 at 16:09

This question came from our site for professional and enthusiast programmers.

Are there more logs available? – Karlson Feb 22 '12 at 15:58
Send us the output of grep q17Nj0RQ003836 /var/log/mail.log – adamo Feb 23 '12 at 8:33

From your log line: [144.92.xx.xx]

That remote server returned a permanent (500) SMTP error code, and so your server will generate a bounce (a Delivery Status Notification). It would be interesting to see what the actual error on the remote server was - usually Sendmail gives a more informative error message and DSN= number.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.