You can use Nethserver whether as a network gateway (firewall with 2 or more NICs) or a standalone server.
First thing: check that port 25 from your router is forwarded to Nethserver IP and that MX record of your public domain points to the public IP of your router.
In dashboard: “email” -> tab “Domains” -> create the domain (“create new” button) or select the domain you want forward (“edit” button) -> tick “Relay to another server” then put the address of your Exchange/Mail server in the box that appears under
In Nethserver 7.5 there’s a problem that you can’t forward the domain of the emails corresponding to the domain with which the Nethserver is configured.
So, if your Nethserver’s name is mygateway.domain.tld, you cannot forward mails for @domain.tld to your Exchange/Mailserver.
If you have the absolute need to forward the domain @domain.tld you have 2 possibilities:
- If this does not cause problems to other services provided by Nethserver, change the name of the Nethserver in something neutral: for istance: mygateway.local.lan
or
- Use these commands:
db domains setprop domain.tld TransportType Relay RelayHost IPOfYourExchangeMailServer
signal-event domain-modify domain.tld