Re: Network Bandwidth Monitoring

[Luke S Crawford <lsc@prgmr.com>]

janskey <janskey_boy@yahoo.com> writes:
> Is there a tool that can monitor bandwidth consumed on a specific user? For example, in my flat network where:
> 
> internet->cisco router->firewall->linux/windows clients & servers
> 
> I want to monitor a client or want to know who's downloading stuff to
> the internet or internal network. I want also to monitor or specify a
> specific bandwidth that he can use so that our internet will not slow.
> Does Squid helps? Any advice? Thanks.

It's not entirely clear what you mean by 'user'  -  if you mean 'IP address'
the tool I use is called bandwidthd http://bandwidthd.sourceforge.net/
I put it on a SPAN port on my old catalyst that mirrors all traffic on my 
uplink port (a hub would work just as well)

as for limiting bandwidth, I use tc, but that requires a Linux router...
here's something chris wrote up about using tc on our Xen setup
http://wiki.xen.prgmr.com/xenophilia/2008/06/traffic-shaping-with-tc-and-xe.html

(the difference here being that essentially my switch runs linux... each 
virtual server has a interface connected to a bridge within my linux Dom0, but
you can do similar things matching on IP addresses instead of interfaces,
if your router runs linux and has only one connection to your network.)


If you mean Linux user or Windows user, the answer is considerably more 
difficult.  Lish suggested squid, and I guess if all your traffic is HTTP,
and you configure everyone to login to the proxy with usernames, that would
work,  but I don't know of any firewall rules in linux that could match or 
count IP packets from a particuluar user, so outside of squid (or other 
proxies) I'm not sure what you are asking for is possible.