public dns service

[Jeff Goeke-Smith]

> -----Original Message-----
> From: linux-user-admin@egr.msu.edu
> [mailto:linux-user-admin@egr.msu.edu]On Behalf Of Marcel Kunath
> Sent: Tuesday, July 04, 2000 11:08 PM
> To: linux-user@egr.msu.edu
> Subject: public dns service
>
>
> Hello,
>
> btw I probably send the memory back in next two days. I put the
> old one in and
> my server doesn't treat me as well anymore. It chokes up fairly often
> now and stalls. Mostly when I use my workstation and I got few things
> open the NFS seems to freeze. It has never done that before. Guess I
> shouldn't touch things. I seem to have bad luck everytime.
>
> Ok to the real topic. My friend just registered a domain
> (www.registryweb.com) over in Australia. On the registration she put in
> the two nameservers of granitecanyon.com the public dns service.
>
> I been just over there reading a bit. It seems to be mostly
> straight forward. I
> had a question about the MX record though.
>
> There seems to be three general types of commands. I am not sure what
> my friend will need.
>
> Here is what granitecanyon.com example looked like:
>
> ; MX records
>
> ; These direct mail delivery agents, like sendmail,
> ; at hosts which have agreed to accept email for us.
>
> ; This assumes that we've arranged with tea.com and
> ; uu.net to provide this email service for us in
> ; advance for coffee.com.
>
> ; The token 'EXTREF' directs nslint to allow external references.
> ; The token 'GLOBALOK' directs nslint to allow global records.
>
> ; MX records for a host to be treated specially
> navy.coffee.com.  IN  MX  10  mail1.tea.com.    ; EXTREF
> navy.coffee.com.  IN  MX  20  mail2.tea.com.    ; EXTREF
> navy.coffee.com.  IN  MX  100 mail.uu.net.  ; EXTREF
>
> ; global MX records for unspecified members of the zone
> *.coffee.com.     IN  MX  10  mail1.coffee.com. ; GLOBALOK
> *.coffee.com.     IN  MX  20  mail2.coffee.com. ; GLOBALOK
> *.coffee.com.     IN  MX  100 mail.uu.net.  ; EXTREF GLOBALOK
>
> ; MX records for email addressed to the zone itself
> coffee.com.       IN  MX  10  mail1.coffee.com.
> coffee.com.       IN  MX  20  mail2.coffee.com.
> coffee.com.       IN  MX  100 mail.uu.net.  ; EXTREF
>
>
> What are the 10, 20, 100 numbers?
>

These are priority numbers.  Lower is higher priority.  This is useful if
there is a chance your mail server will be down and you have an arrangement
with somebody to cache your mail till your server comes back up.  I don't
currently have any such arrangement.  In that case you can just set the
number to an arbitrary value as it has no meaning when there is only one
server for mail.

> If my friend now runs a mailserver on machine mail.thedomain.com
> and likes it
> to receive mail to @mail.thedomain.com and @thedomain.com which
> one of these
> zone MX records should we use?
>
> ; MX records for email addressed to the zone itself???
> thedomain.com.    IN  MX  10  mail.thedomain.com.

That record looks pretty good to me.  By default, IIRC, most MTAs will fall
back to attempting to send mail to the machine its self if there is no MX
defined for it. To be safe you might want to set up a record like:
mail.thedomain.com IN  MX 10 mail.thedomain.com   , But the more I think
about this, I think this might set up an MX loop, so that might not work
correctly....

It's late, I'm tired, and I'm not thinking clearly.  ( Still dusting all the
gunpowder off from tonight)  I can only hope at this point that I've done
more good than harm.

--Jeff Goeke-Smith