#!/usr/bin/perl -w

use strict;

my $file = '/var/tmp/exim_deny';

my $ip = shift;

die "No argument" unless defined $ip;

die "Invalid argument |$ip|" unless $ip =~ /^\d+\.\d+\.\d+\.\d+$/;

 # (at this point you _could_ take a look in the file and see
 # if the address is already there - can happen occasionally
 # e.g when two concurrent dictionary-scan attacks are detected
 # from the same IP).

# Since we're doing an append we can ignore file locking...
# (and it's not going to be the end of the world if we sometimes
# manage to list the same address twice...)

open OUT, ">>$file" or die "Couldn't open file, $!";

my $datestamp = scalar localtime;

print OUT "\n\# $datestamp\n$ip\n";

close OUT;