What DNS server can/should I use to look up IP address?

[CL328]

Hello,

I am running Sawmill (traffic analyzing software) and want to do reverse lookups, but I need to enter in a DNS server.

Which one do I use?

I'm on Road Runner, but it sucks or doesn't work.
Aren't there DNS servers for the public?

Also, why do some IP address have names and other just stay the number? Is it because the DNS server does not know the domain name?

thanks
-Larry

 

[rybo]

You can find out your DNS servers by typing in the command prompt the following:

ipconfig /all

(For Windows, of course)

Some people still just use the IP address and don't have a domain name (which resolves to your IP address).

 

[sleipnir214]

Looking up reverse DNS is never a quick operation. Unlike the domain names searched by forward DNS, there is no registered server of authority for an IP address. When you do a PTR query, the query has to go out blindly across DN servers until one responds with an answer. Nobody's DNS is quick on reverse lookups.

Some IP addresses will always be unresolvable into names. BIND, for example, requires you to set up each reverse zone by hand, so a lot of admins don't bother. There are apps that will parse all your forward DNS zone files and generate the reverse information, but if you have anything unusual in your zone file structure, all the apps I've tried barf.