Hi everyone ! I think I'm doing this wrong (read: I'm so sure this is wrong ) I've setup a domain (domain.tld) which has a MX record with prio 10 that goes to a non ISPConfig mail server and setup the domain in ISPConfig as wel as an e-mail domain so I am allowed to relay with this domain trough the ISPConfig mail server using the external mail server. So I have configured the external mail server to relay to the ISPConfig mailserver which then again mails to the outside world (this due to a bad provider on the external mail service which is more blacklisted than not.) This part works great, mail flow works perfect etc. Then the part where it goes wrong So I wanted the ISPConfig mail server to be a backup as well in case the external mail server fails to respond, goes down etc. So what I did is setup mail routing to relay all mail to the external mail server, added an MX Record with lower prio to the ISPConfig mail server for domain.tld. This is the part where you should nod your head and go no no no no, that's wrong because you have the domain listed in e-mail routing as well as in e-mail domain. True, since mails sent to the backup server (ISPConfig server) will bounce with the message that there is no user available for this domain on the server which seems pretty logical. Now the part where I ask everyone else's expertise Should I setup the transport manually? But will I be able to relay trough the ISPConfig server? Basicly what I'm trying to setup in short is: External mail service that relays trough the ISPConfig mail server AND the ISPConfig mail server keeps a backup of the messages in case primary mail server fails to respond or goes down. Possible ? Should I setup the config for this manually? (not really sure about this since I don't want to break my fantastic ISPConfig system as it is running Production rather then Dev.) Thanks for your response !