dovecot: auth: Error: DNS lookup for xxx failed: Name does not resolve

[John Stoffel]

Marc> I had a working container with dovecot configured as proxy. And
Marc> all of a sudden I am getting these messages 'dovecot: auth:
Marc> Error: DNS lookup for roosit03 failed: Name does not resolve'
Marc> Pinging/nslookup these hostnames is ok

Does nslookup work inside the container?  Sounds to me like the setup
isn't working properly, but it's hard to know unless you give us more
details.  Can you spin up another container with the same config but
not running dovecot to do a check on DNS resolution?

Does the container's logs give you more details?  How often do you
stop/restart the container?  I would think that Dovecot in a container
isn't really ideal since you need to access the mailstores, and
somehow you get email delivered to the mailstore by
postfix/sendmail/exim or some other tool.

John