How can we set reverse DNS for a dedicated server. I want to add 5 domains in this server. But I don't want to tell anyone who is the ISP. If anyone trace the domain from visual route or anyother pinging software. They don't come to know about the ISP.
Please tell me how can I do it.

Your ISP will need to delegate the in-addr block to you. This is probably more of a pain than it is worth, unless you have a lot of IP addresses. Your best bet is to contact them and have them setup the PTR records on their DNS server.

Although it really won't make a difference. If someone wanted to know who that IP block belonged to, they could find out anyway :D.

Could you please tell me how can we do reverse DNS.
Is there anyway through which we can hide our NOC :)

Sure, its just like a normal zone file, but you use the identfier address. For instance, one of our netblocks is: 63.80.246.0/24. The name of the zone file would be 246.80.63.in-addr.arpa.

You can find out more information about setting up reverse DNS here:

http://www.troubleshooters.com/tpromag/9811/dns.htm

Again, it won't do you any good to setup reverse DNS unless your ISP delegates the block to you.

And no, you cannot hide who your NOC is, unless you get your IP Addresses directly from ARIN (or the netwokr number provider is). You post from IP address 61.11.24.50. I can query the whois database for APNIC (Apsian Pacific Network Information Center) and find out this:

inetnum: 61.11.0.0 - 61.11.31.255
netname: DISHNET
descr: DISHNETDSL LTD
descr: 19, Cathedral Garden Road
descr: Pune
descr: CHENNAI
country: IN
admin-c: DIH1-AP
tech-c: DIH1-AP
mnt-by: APNIC-HM
mnt-lower: MAINT-IN-DISHNET
changed: hostmaster@apnic.net 20000321
changed: hostmaster@apnic.net 20000927
source: APNIC

Similarly, if you were to query ARIN on the block I gave you:

UUNET Technologies, Inc. (NETBLK-UUNET63) UUNET63 63.64.0.0 - 63.127.255.255
Spectrum Computers (NETBLK-UU-63-80-246) UU-63-80-246
63.80.246.0 - 63.80.246.255

Spectrum Computers was our original company name, but you now know that we get our IPs from UUNET.