Sendmail DSN: Data format error

[Ray Pemberton]

We had a problem with DNS on our mail relay server, which resulted in emails being lost. Can sendmail be set up to resend an email we get the error below:-


Feb 6 02:07:26 ssn4000d sendmail[7514]: CAA07512: to=, delay=00:00:24, xdelay=00:00:24, mailer=relay,
relay=ukproxy.torex.com [159.170.4.84], stat=Data format error
Feb 6 02:07:26 ssn4000d sendmail[7514]: CAA07512: CAA07514: DSN: Data format error

[Peter Godron]

Ray,
what is the problem with the DNS ?
Have you set you DM macro correctly in sendmail.cf? (Should be your domain name)
Are all messages impacted by this?

[Steven E. Protter]

Shalom Ray,

nslookup sbs.nhs.uk

If the lookup fails, sendmail will not be able to deliver the mail.

Except if you are using the DS parameter of sendmail to do relay.

In that case, make sure nslookup for ukproxy.torex.com works. Make sure you can ping it or telnet ukproxy.torex.com 25 the server.

Make sure it allows the server we are working with, ssn4000d to relay.

SEP

[Ray Pemberton]

emails worked fine before and after the DNS issue. We had to kill off and restaart the named process on the mail relay server. The messages that were sent during the DNS down period were lost, can this be avoided as the emails are critical.

[Ivan Ferreira]

If DNS down is your problem, you can configure a secondary DNS server. If Mail server down is your problem, you can configure a another MX resource record.