[cvsnt] Re: CVSNT 41a >10 secs delay with Reverse DNS disabled - any ideas

Tony Hoyle tmh at nodomain.org
Tue Jul 20 22:58:31 BST 2004


Greg Smith wrote:
> Hi Tony,
> 
> Changing to pserver did indeed stop the delays, so many thanks for that.
> 
> Do you have any suggestions of where to look to find out how to set up
> Reverse DNS correctly on the server? All the doc I can find seems to start
> with the premise that you know all there is to know about the subject before
> you start.
> 
It depends on the server... You just setup a domain x.y.z.in-addr.arpa 
(where x.y.z is the last 3 numbers of your domain, in reverse) with PTR 
records for each server.

eg. if you have a machine

fred IN A 192.168.1.32

you need a reverse in 1.168.192.in-addr.arpa

32 IN PTR fred.

btw. you won't get the delay if your DNS server simply refuses to serve 
the x.y.z.in-addr.arpa domain...you're getting the delay because your 
server says it is authoritative for the reverse DNS then refuses to 
actually return any data... so one option is to go the other way disable 
it on the server completely (not that I would recommend such an action...)

If it's working you can run nslookup on either name or IP and get the 
other one.. eg:

C:\>nslookup tucker
...
Name:    tucker.local.nodomain.org
Address:  192.168.44.254

C:\>nslookup 192.168.44.254
...
Name:    tucker.local.nodomain.org
Address:  192.168.44.254

Or even:

C:\>nslookup -query=ptr 254.44.168.192.in-addr.arpa
...
254.44.168.192.in-addr.arpa     name = tucker.local.nodomain.org
44.168.192.in-addr.arpa nameserver = dns0.nodomain.org
dns0.nodomain.org       internet address = 213.208.99.114

Tony



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