Thanks, edge. I already read the same answer to a post asking nearly the same question.
But until now I had to ask nothing to my ISP. We are currently running BIND as primary and backup DNS servers. When we have to set some reverse lookup we just add an entry to the zzz-qqq.uuu.yyy.xxx.IN-ADDR.ARPA. where zzz-qqq is the IP ranges assigned from the ISP to our subnet.
An example for that entries is:
58 IN PTR mail.mydomain.com.
59 IN PTR ftp.mydomain.com.
where 58 and 59 are the last part of the public IP address of the mail and ftp servers.
We have not a /24 subnet, so maybe the first step in reverse lookup is done by the ISP pointing to our currently running DNS (BIND) and then is reversed by us.
This can explain the problem: actually MyDNS is still in test, so is not "declared" to the internet.
But if I execute
#dig @xxx.yyy.zzz.fff -x xxx.yyy.zzz.qqq
(where xxx.yyy.zzz.fff is the IP our new-MyDNS Server and xxx.yyy.zzz.qqq is the IP we want to reverse), we should work around that problem, because we asking directly to our new server to reverse-lookup the IP xxx.yyy.zzz.qqq
Whre am I wrong?
In any case, suppose we have a /24 subnet: how can we, within MyDNSConfig, setup the reverse DNS for our servers? How can we "declare" that xxx.yyy.zzz.qqq is for mail.mydomain.com and xxx.yyy.zzz.hhh is for ftp.mydomain.com ?
I found the answer by myself (supposing we have a /24 subnet xxx.yyy.zzz.0-255):
in MyDNSConfig just create a new zone named "zzz.yyy.xxx.in-addr.arpa.", then add PTR records inserting as "Name" the last number part of the IP of the server you want to reverse (ie "qqq") and inserting in the Canonical Hostname field the complete hostname (ie "mail.mydomain.com.")
Now, if my ISP reverse only a part of the /24 subnet, maybe him reverse something like "aaa-fff.zzz.yyy.xxx.in-addr.arpa.", so I have to change my zone name from "zzz.yyy.xxx.in-addr.arpa." to "aaa-fff.zzz.yyy.xxx.in-addr.arpa."
I will try if it works.
Thanks for pointing me in the right direction
Last edited by gdavid; 14th October 2010 at 12:45.