[pmwiki-users] [OT] Strange list DNS issues

[Joachim Durchholz]

Robin wrote:
> However I'm not totally sure what a domain without a defined MX
> should return,

No MX record. DNS doesn't interpret, it is simply a store of records. 
Clients are expected to make sense of what they find.

A missing MX record means that the server is its own MX.

Recommended practice is to have two MX records. One would go to 
pmichaud.com itself, the other would go to a backup mail server.

 > except there is no authority section, which strikes me as a
> little odd.

That's actually normal. It says that the information that you got is 
from a DNS cache, and that you should ask the machine listed in the NS 
record if you want a more current copy of the data. (Not sure whether 
that NS record will directly lead to the authoritative server; maybe one 
might have to follow the chain of NS records.)

 > I'm also not sure why it isn't falling back to the A record

My guess is that this is a consequence of some other problem (probably a 
configuration issue). Normally, fallback to the A record is not a 
problem. (OTOH it's rare that a machine doesn't have an MX record, so 
you may have triggered a sleeping bug.)

Regards,
Jo