Error message when transferring ironport

[anette.amor.202]

When the mail server transfers messages to ironport the following message:

Error transferring to <IRON PORT IP>; SMTP Protocol Returned a Permanent Error 553 #5.1.8 Domain of sender address <xxx@midomain.cl> does not exist

[Paul Cardelli · Accepted solution]

This appears to be a DNS resolution issue, doe the appliance have access to the configured DNS server, and can you test that the DNS server can resolve the domain in question?

[anette.amor.202]

Paul, Thank you
Indeed the DNS defined in ironport was not working. There is a way to monitor this service and alarmed when it happens, that , failing the DNS internal emails sent to internet were rejected with the error reported