I send (some) E-Mail direct to my home server machine using SMTP, I used to do this using a sub-domain of my domain isbd.net which is hosted at Gradwell. I added a CNAME record for 'home' to the zone file for isbd.net and gave my static ADSL address as the value for this record.
Thus mail forwarded to 'chris@home.isbd.net' arrived at my home server machine (subject to NAT forwarding and firewall of course) and was delivered by postfix to user chris.
I now have a dedicated domain for my home server(s) and I'm struggling to get things working.
The new domain is zbmc.eu, I have set up the zone file at the domain hosting as follows:-
imap 10800 IN CNAME access.mail.gandi.net. www 10800 IN CNAME zbmc.eu. smtp 10800 IN CNAME relay.mail.gandi.net. pop 10800 IN CNAME access.mail.gandi.net. blog 10800 IN CNAME blogs.vip.gandi.net. webmail 10800 IN CNAME agent.mail.gandi.net. @ 10800 IN A 84.45.228.40 @ 10800 IN MX 10 mws.zbmc.eu. mws 10800 IN CNAME zbmc.eu.
(Most of this is unchanged from the default setup of course)
The 'www' CNAME entry is working fine, going to www.zbmc.eu shows my web pages (or more my lack of web pages!).
I'm not at all convinced that I have the MX record right yet though, nor am I convinced that I actually need that 'mws' CNAME record. Could I just set the MX record to:-
@ 10800 IN MX 10 zbmc.eu.
Can one of the alug gurus elucidate please.
... and do I *need* a second MX (backup) record or will the sending SMTP server just back off and try again if my server is down for a short while?