Reject domains containing capital letters

MailCleaner Support
Added about 1 month ago

Domain names shouldnt have any capital letters in them according to RFCs so we decided to forbid this use for sending domains as this is most of the time used to circumvant anti spoofing tools.

Since this is compliant to RFCs and since using those capital letters is mainly made to spoof addresses, we decided to activate it for everyone by default.

This feature is based on the recipient domains that is to say you can enable/disable this feature for any domain you are hosting.

To change this feature settings go to

Configuration->Domains-> -> Filtering

and check or uncheck

Reject domains containing capital letters

then restart the Incoming MTA for all servers of your cluster in

Monitoring status

To enable this feature on all domains of your cluster, you can run on the master node of your cluster

echo "update domain_pref set reject_capital_domain=1" |mc_mysql -m mc_config

change 1 to 0 if you want to disable it then to forget to restart your Incoming MTA.