> My brother uses dyndns.org and want to use it for his email and web.
> Let's say he has example.com and his dyndns entry is example.dyndns.org.
>
> for example.com:
I'm assuming you meant "example.dyndns.org" there; if not, the rest of my
post will be entirely bogus...
> IN NS ns1.123reg.co.uk.
> IN NS ns2.123reg.co.uk.
> IN MX example.dyndns.org.
> www IN CNAME example.dyndns.org.
> Fab. Now we just want to get example.com working too, let's try:
> IN CNAME example.dyndns.org.
>
> Darn, firstly this doesn't appear to be valid according to quite a few
> resources
Well, it's valid as far as it goes (which probably wasn't as far as you
wanted). What were you trying to do with that record?
> (although it does seem to work with limitations). Firstly
> CNAMEs override all other types (so we effectively remove the two NS
> and MX record), we also lose the SOA record too.
Not really. You never *had* NS or SOA records for example.com (unless
there are other records not listed here). The CNAME only redirects the DNS
lookup for that one record (the A record by default); the rest of the zone
still needs setting up.
> Oddly enough http://www.intodns.com/ doesn't have much of a problem -
> it complains about missing glue records, MX and SOA.
Well, yes. They're missing :-)
> I just wondered if anyone had insights/alternatives (he's going to
> stick with his cname ATM since "it seems to work" (I don't like it one
> bit). My recommendation was to use the first approach and point the
> example.com record to a friendly A record (i.e. my static IP) and then
> do a permanent HTTP redirect from there.
CNAME is expensive in DNS terms (it adds another lookup), so it is always
preferable not to use them if that makes sense - in this case, it's
probably quite a good idea, if you really do want to this sort of setup (I
wouldn't - I suspect you're going to run into problems with blocklists
etc. if you're trying to run a MTA on a dynamic IP).
Vic.
