Skip to Navigation (at bottom of page). (at bottom of page).

The short guide to adding an MX record :-

First make absolutely certain the names aren't being used by using dig or nslookup to do a thorough search (including MX records).

The files you need to modify are in bombadil:/root/dns The two files that need changing are apana-hunter (name-> number) and 156.14.203.in-addr.arpa (reverse lookup. ie. number-> name)

Create a tarball backup of the files before you make any changes. You should just need to add the MX records to the apana-hunter file. You'll also want to change the serial number in the reverse lookup file as well, as the "submit-dns.pik" script bundles up both files and mails them to the dns-update address.

Run the "submit-dns.pik" script and wait for notification of the change going through.


From Gavin Condon Re: MX records

On Mon, Mar 13, 2000 at 11:21:07AM +1100, Ross Slade wrote:
> Ok, dig doesn't make much sense to me, but nslookup indicate skunk and
> polecat are available....

dig is great for reverse lookups.. like dig -x 203.14.156.3 (gives all the aliases for bombadil)

Using nslookup it's best to "set querytype=ANY" when checking to see if a name is being used.

> Proposed entry:
>
> -------------
> brushtail IN MX 10 skunk.apana.org.au
> IN MX 20 polecat.apana.org.au
> IN MX 100 mail.hunter
> IN RP postmaster.brushtail.apana.org.au
> -------------
>
> Am I close?

Kinda close. Actually it's arse-backwards.. ;) What you're saying there is that any mail for brushtail should first be sent to skunk, (which doesn't exist and will fail), then try polecat, (also doesn't exist and will fail) finally send to mail.hunter, which will work.. :)

Mail for skunk and polecat just wouldn't work as when the mail transport program tries to lookup the names skunk and polecat it wouldn't find _any_ entries and would simply inform the sender that the machine's don't exist.

New entries will look more like
-------------
skunk IN MX 10 brushtail
IN RP postmaster.brushtail.apana.org.au.

polecat IN MX 10 brushtail
IN RP postmaster.brushtail.apana.org.au.
-------------

Sendmail looks up Skunk, sees it needs to go to Brushtail, looks up Brushtail sees it needs to go to mail.hunter which (with correct mailertable entries) actually accepts the mail and batches it into the brushtail UUCP feed.

> My "Using Linux" mentions "A" and "MX" entries but doesn't mention "TXT"
> or "RP" ones unfortunately but I gather the integer on MX records
> detirmine the final resting place of mail - the highest number being the
> end of the line for a message to any of the listed MX records?

RP - Responsible person
(ie. The person to contact when the sh*t hits the fan with the machine. It's actually an email address. postmaster.brushtail.apana.org.au. == postmaster@brushtail.apana.org.au)

The small "priority" number in an MX record means the "prefered" destination. If that destination is unreachable it will try one of the larger numbered destinations (or a random selection if there is more than one destination with the same "priority" number).

Hmmm, UUCP sites are not listed in 156.14.203.in-addr.arpa? Can't see brushtail anyway...???

Sites that only receive a UUCP feed generally don't have/need an IP address to be allocated to them. If they don't have an IP number, then there's nothing to "reverse lookup" as they can't be refered to by just a number. (A site can still have an IP _and_ be a UUCP site in which case there _will_ be a reverse lookup for the site)


> Its name at the moment is 'valar' (a Tolkien group of characters 'the
> guardians of middle earth' of which Tom Bombadil is one)....and we assigned
> it the IP of 203.14.156.24.
>
Thinking in terms of powers of two and multiples of 8, 24 is the first IP in the third /29 subnet and from an organisational point of view an IP of 23 or less (22 is free?) could make it easier to blanket all the servers and dialups with 0/29+8/29+16/29 and all the statics with 24/29..?/?