rDNS - Reverse DNS lookup (rDNS) is a process to determine the hostname or host associated with a given IP address or host address. (wikipedia).

Any want of you facing the problem, unable to lookup your rDNS for your DNS server?.I also got this problems with my rDNS lookup. After a few day seek for the solutions how to make sure the rDNS work properly, finally i found the solution. Any local/public IP from Telekom Malaysia (TM), must ask from their site to enable the rDNS.By default they not allowed the rDNS if we are not request it.To request it we can email : dnsteam@tm.net.my / dndadm@tmnet.com.y or lock report to iCOMS.After do want of this method, finally my rDNS work properly. So far their respond better.

Two-in-one DNS server with BIND9

• This tutorial shows you how to configure BIND9 DNS server to serve an internal network and an external network at the same time with different set of information.

1. The problem
It is a typical problem in organizations that are growing that they have to resolve two problems at once:

• To have a DNS server for the internal network of the company because long ago there were already too many computers to remember their IP and even too many computers to maintain a set of host files

• To have a DNS server for the external servers, for external clients, etc.

• To solve this problems become a bigger problem when the growing organization can’t supply more resources than one DNS server3. It is a bigger problem because if you just configure your server with all your names, public and private, you’ll end up polluting the Internet with private addresses, something that is very bad, and also showing the world part of the topology of your internal network. Something you don’t want a possible attacker/cracker to have.

• The other part of the problem is that for efficiency you may want to resolve to internal IPs when you are inside and external IPs when you are outside. Here I am taking about computers which have public and private connections.

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Theory Behind Caching-Namerserver and BIND 9:

• Caching-Nameserver is a type of nameserver that will resolve a web addresses (domain names) from its next or master DNS, and will keep those entries in cache, after first time resolution it will resolve DNS queries locally, untill its TTL (Time To Live) is expired.

• BIND 9 is used to resolve domain resolution queries from it own database, as it is SOA (Start Of Authority).

• So now it is clear that in our setup the caching-nameserver will be used to resolve domain names externally (internet), while BIND 9 will be used to resolve domain names from our local network (internally).

• Now we have caching-nameserver and BIND 9 hammer in our hands, lets start fixing it.

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