Re: From IP to domain name

[w trillich <will@pinncomp.net>]

"Ivan J. Varzinczak" wrote:
>         I'd like to know if someone can give me any sugestions about
> how I can discover the domain name given an IP address. For example,
> if I have the IP address 205.188.146.23, I would like to discover what
> the domain name is, in that case, aol.com.
>         I've tried to use nslookup, but I've had some problems in
> setting the servers, because perhaps I'll need the "root" servers on
> internet and it doesn't work very well.
>         Thanks in advance!

the 'reverse-name lookup' construct swaps the order of the IP
numbers and appends '.in-addr.arpa' to the end, so that
	123.45.67.89
would be looked up as
	89.67.45.123.in-addr.arpa
and to keep your server from appending any local 'search'
domains (if you're at 'myserver.com' the sought address might
be mangled into '89.67.45.123.in-addr.arpa.myserver.com' if
you don't) then be sure to put the trailing DOT at the end:
	89.67.45.123.in-addr.arpa.
like this:

	% nslookup
	Default Server:  localhost
	Address:  127.0.0.1
	
	> 23.146.188.205.in-addr.arpa.
	Server:  localhost
	Address:  127.0.0.1
	
	Name:    23.146.188.205.in-addr.arpa

[woo. not very informative, there.]

	> set q=any
[now we'll get ANY records available.]
	> 23.146.188.205.in-addr.arpa.
	Server:  localhost
	Address:  127.0.0.1
	
	23.146.188.205.in-addr.arpa     name = www2.aol.com
	146.188.205.in-addr.arpa        nameserver = dns-01.ns.aol.com
	146.188.205.in-addr.arpa        nameserver = dns-02.ns.aol.com
	dns-01.ns.aol.com       internet address = 152.163.159.232
	dns-02.ns.aol.com       internet address = 205.188.157.232
	>

voila!

if you get into setting up your own DNS, you'll get quite
familiar with this stuff. (see 'man named' and 'man named.conf'
for the scoop.)

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