#!/usr/bin/perl -w

use strict;
use warnings;

my $PingHost = '192.168.23.1';
my $ExpectedRedirect = '192.168.0.10';
my $MailTo = 'postmaster@domain.net';

my $ip = `ip route flush cache`;

open( INPING, "ping -c 10 $PingHost|" ) || die "ping open failed";
while( my $line = <INPING> ) {
  next unless( $line =~ /Redirect Host\(New nexthop: (.*)\)/ );
  next if( $1 eq $ExpectedRedirect );

   open( OUTMAIL, "|mail -s 'VPN Unexpected Redirect: $1' $MailTo" ) || die "pipe to mail failed";
   print OUTMAIL scalar localtime();
   print OUTMAIL "\n\n";
   print OUTMAIL "VPN NETWORK\n";
   print OUTMAIL "Received an unexpected redirect to: $1\n";
   close(OUTMAIL) || warn "bad pipe close";
}

close(INPING) || warn "bad pipe close";