On 09 Aug 15:01, Chris G wrote:
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.
MX pointing to a CNAME is a violation of the DNS policy, MX records should *always* resolve to A records, not CNAME records.
You can (in your setup, though it's not what I'd do), use: @ 10800 IN MX 10 zbmc.eu.
(Most of this is unchanged from the default setup of course)
A default setup would *not* have the MX pointing to a CNAME.
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.
Yes, you can. I wouldn't. I'd setup: mail 10800 IN A 84.45.228.40
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?
There's very very rarely a need for a secondary MX record, it's only really of use if you're going to be offline on the primary MX for > 1 day and the TTL of your MX record is set to a long time, otherwise, you just change the MX record during downtime. Other mail servers will queue nicely for you for (usually) up to 3 days, or generate bounces to the senders.
Personally, I wouldn't be squeezing SMTP data over a ADSL line, I don't trust BT (or the LLUs) that far... My mail sits outside my home connection on a VM that I can access from anywhere (via imap), and post through from anywhere (using smtp and authentication on the submission port), and I usually use mutt directly on there (unless I want to sign things, etc, then I use the magic mutt config on my laptop instead, as I tend to use ssh as the transport for the imap stream, thus using my ssh key that I've got ssh-agent and a passphrase for, rather than having to give mutt my imap password).
Thanks,