#!/usr/bin/perl -wT
use strict;
use CGI qw(header param);

# Assume your form inputs are called ip1 and ip2
my (@ips) = (param('ip1'), param('ip2'); 

# Untaint the IP data
# Note: This is very 'quick and dirty', and [mirod]'s
# solution below is much better.
foreach (@ips) {
  s/^(\d+\.\d+\.\d+\.\d+).*$/$1/;
}

# print HTTP header
print header(-type => 'text/plain');

# Call BING (I'm guessing at the syntax)
# and print the output
print qx(BING $ips[0] $ips[1]);