LCDB: Linuxplanet adds "Today's Tip" Section (printable)

Originally published: Tuesday, 26 October 1999	Author: James Andrews
Published to: news_learn_support/Support News	Page: 1/1 [Standard view]
Linuxplanet adds "Today's Tip" Section Linuxplanet now has a Tips section, which is updated daily

Here is one of the Tips

Analyse tcpdump output with a perl "one liner"

run tcpdump -c 5000 >file1

and then analyse the output

perl -n -e 'next unless(/^\S/ ); @a=split(/\s/);$s{$a[1]}++; END {@o=sort { $s {$b} <=> $s{$a} }keys %s; for(@o[0..10]) { print ``$s{$_} $_\n''}}' file1

Do this repeatedly to see what is generating the traffic on your hosts interface

Here is the same thing as a short script


#!/usr/bin/perl -w 
while(<>)
  { next unless(/^\S/);
    @a=split(/\s/);
    $s{$a[1]}++; 
  } 
  @o=sort { $s{$b} <=> $s{$a} }keys %s; 
for (@o[0..10]) { 
  print ``$s{$_} $_\n'';
                     }

If you want something more sophisticated then the Ethereal package is worth a look