Perl TCP sniffer

[awolff01]

Hello,

I am wondering if anybody knows of a network sniffer for perl?

I need to log network traffic going out of my machine thru my tcp ports to get the exact syntax of cgi call my browser is making.

Thanks.

 

[usige]

You can use the Net:capUtils and NetPacket modules to build a primitive sniffer in perl.

Here is a quick http sniffer in perl (modified from NetPcket::TCP man page):

#!/usr/bin/perl -w

use strict;
use Net::PcapUtils;
use NetPacket::Ethernet qw(:strip);
use NetPacket::IP qw(:strip);
use NetPacket::TCP;

sub process_pkt {
  my($arg, $hdr, $pkt) = @_;

  my $tcp_obj = NetPacket::TCP->decode(ip_strip(eth_strip($pkt)));

  if (($tcp_obj->{dest_port} == 80)) {
    print($tcp_obj->{data});
  }
}

Net::PcapUtils::loop(\&process_pkt, FILTER => 'tcp');

Your platform must support libpcap to use the Net:cap and Net:capUtils modules.

Hope that helps.

 

[fishiface]

...sounds like you just need to monitor port 80 rather than write your own sniffy thingy. How about tcpdump (

http://www.tcpdump.org)?

"As soon as we started programming, we found to our surprise that it wasn't as easy to get programs right as we had thought. Debugging had to be discovered. I can remember the exact instant when I realized that a large part of my life from then on was going to be spent in finding mistakes in my own programs."
--Maurice Wilkes