Get server name from ip address

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I need to find the name of the server from an ip address. Currently I can find the IP address of a server name but want to reverse this and find the server name from an IP address that I have. Please advise. Here is a script to fetch ip address from server name:

foreach $host (@ARGV)
{
($name, $aliases, $addrtype, $length, @addrs) =
gethostbyname($host);  #gethostbyname IS A PERL

print "$host:\n";

foreach $a (@addrs)

{
$i = join(".", unpack("C4", $a));
if( ! $i ) 
{
print ">>>>>>$i<<<<<<\n";
print "NOT FOUND\n";
}
else
{
print "$i\n";
}
}
}
[download]

Comment on Get server name from ip address Download Code

Replies are listed 'Best First'.
Re: Get server name from ip address by Fletch (Bishop) on Apr 09, 2004 at 17:24 UTC
`perldoc -f gethostbyaddr`, Net::DNS.	[reply] [d/l]
Re: Get server name from ip address by eXile (Priest) on Apr 09, 2004 at 17:52 UTC
A note on using name to IP / IP to name translations using DNS: All answers you get from these translations depend on how the specific DNS domains are set up. Without going into details, when doing a name to IP translation and then doing a IP to name translation (a so called 'reverse lookup') you might end up with a different name than you started with. For instance for 'www.perlmonks.org' your scipt will output: `209.197.123.153 66.39.54.27` [download] When doing a reverse lookup on these addresses (I used the 'dig -x <addr>' to do this) you'll get: `perlmonks.pair.com` [download] and `ads.perlmonks.org` [download] This is because forward and reverse DNS don't have to be the same. And to complicate things even further DNS-records change in time. So an answer you got for a 'gethostbyname' query today can be different from an answer you got yesterday.	[reply] [d/l] [select]