"Sender domain must exist" error while receiving mails from certain domain.

Issue

"Sender domain must exist" error while receiving mails from certain domains.

Solution

For 'Sender domain must exist' error, we can try a workaround by adding an exception.

We can add an exception for incoming mails from certain domains for "sendercheck" attribute.

We can add an exception using the following Command,

CLI > exception add smtp:in sendercheck "domainname" off

Instead of "domainname" we can also use following options,

1. IP address--exact match (implicit or explicit /32 netmask)
2. IP address - most specific netmask (netmask /24 wins over /16)
3. *.domainname - longest name wins (wildcard "*" refers to a subdomain)