Alright
A reverse IP lookup is the opposite of a domain lookup. For example the main purpose of the who internet domain name system (dns) is to translate a domain (domain.com) to an IP (1.2.3.4) which is required for your computer to find a webserver on the internet. Now email program often do a security check, and try to figure out the domain FROM the IP that's connecting to make sure the sender is who they say they are. This is a called a reverse IP lookup.
domain lookup:
domain.com -> 1.2.3.4
reverse ip lookup:
1.2.3.4 -> domain.com
Now, so setup a reverse IP lookup, it has to be done manually becuase it's only has to be done once per IP, and much of the time, datacenters do it for you, so you don't even need to worry about it.
When time becomes available, we'll get DA to do it automatically for people, but it doesn't exist at the moment.
For the case that you do need to do it yourself, you can do the following:
edit /etc/named.conf and add:
Code:
zone "4.3.2.1.in-addr.arpa" IN {
type master;
file "/var/named/hostname.db";
};
Note that the numbers for the IP are backwards in that file. Then edit /var/named/hostname/db, and set:
Code:
$TTL 0
@ IN SOA ns1.domain.com. root.domain.com. (
2003082300
7200
3600
1209600
86400 )
NS ns1.domain.com.
NS ns2.domain.com.
PTR domain.com.
The ns1/ns2 values should be any nameserver that you have on your machine. root.domain.com is an email address (
[email protected], but replace @ with . ) The domain.com beside the PTR value is the actual value that is returned. Generally this will be set to your server's hostname, but ultimately, it's the value you want the reverse IP to return.
Save that, then just type
and that should load in the new settings. You can test your new reverse ip to make sure that it's working by typing:
Code:
dig -x 1.2.3.4 @127.0.0.1
This willl ask your own copy of named what it's returning. Once that's working, it's out of your hands. As mentioned before, some datacenters have control of the reverse IP, so anything your create might not have any effect.
John