Clarification - Reverse DNS Setup

Barry Margolin barmar at
Fri Jan 7 23:02:47 UTC 2005

In article <crn3f4$1u5o$1 at>, originalremfan at wrote:

> We've just purchased T1 service and our provider will be delegating
> reverse DNS for the block to our name servers.  I've done reverse DNS
> before, but always on class C's, which have been very straight
> forward... This is not!  I have read the Bind book, browsed every Bind
> reference on the net and I've come to the point where the more I read,
> the more confused I am!  I need some clarification, please.
> My ISP says that they will be delegating
> 160/ to me (just pretend the IPs are real).
> I've set up the following in my named.conf:
> zone "162.160/" {

This should be:

zone "160/" {

i.e. the same name as the domain that your ISP told you they're 
delegating to you.  Where did the "162" come from?

> type master;
> file "db.162.160-";
> allow-query { any; };
> };
> and the zone file:
> $ORIGIN 162.160/

This origin statement isn't needed, since the default origin is the zone 
name.  But if you have it, it should be:

$ORIGIN 160/

> $TTL    1D
> @       IN      SOA
> (
> 2005010702; Serial
> 604800         ; Refresh
> 86400         ; Retry
> 2419200         ; Expire
> 604800 )       ; Negative Cache TTL
> ;
> @       IN      NS
> 162     IN      PTR
> So my question is - is this going to work?  Have I done it right?
> Since the ISP hasn't set up the CNAMEs on their server yet, I don't
> think I have any way of testing it yet.  If this isn't right, can
> anyone clarify the setup for me?  Like I said, I've tried my best to
> set it up, but it's very confusing (at least for me!!).

Correct the above errors and it should work.

You might also want to change the filename to match the corrected zone 
name, but that's not critical -- filenames are arbitrary.

Barry Margolin, barmar at
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

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