Ports doubt, check network performance...?

[Nikos Vassiliadis]

On Wednesday 05 July 2006 02:01, perikillo wrote:
> On 7/4/06, Nikos Vassiliadis <nvass at teledomenet.gr> wrote:
> > On Tuesday 04 July 2006 03:49, perikillo wrote:
> > >    Hi people.
> > >
> > >     I have some problems on my network, and i want to use my freebsd
> > > box to see if i can find the problems on my network, we have two
> > > networks in two countrys connected by a private link, but i have seen
> > > just a couple a weeks ago that we have some problems between both
> > > links, we are lossing packets if i ping some server on the other link,
> > > some times i get 36% of packets loss, is to but to much on bussines
> > > hours.
> >
> > 36% packet loss is very high, it will almost make TCP unusable.
> > ping is your tool. Use -s 500 to 1500 to simulate some-how real traffic
> > situation. I guess you have a point-to-point link between the two
> > offices, connected to a router? Do you administer these routers? Do know
> > your bandwidth utilization? Are you sure your link is OK? check this with
> > your service provider.
> >
> > Either you link is bad or you use all your available bandwidth.
> >
> > >     I want to use my freebsd box running 6.0 but just want to know if
> > > some one could recomend me wich ports to check to see if i can find
> > > wich device is causing this problem.
> >
> > FreeBSD can not help you much with this. Unless FreeBSD is the router
> > in question. Or you could pass all traffic from a FreeBSD box in order to
> > know what's going on. something like this
> >
> > central-switch------FBSD------router-1=====router-2
> > [--------------------LAN--------------------] [-----WAN-----]
>
>    No i dont administer those routers, i need to check if the problem
> is our network or the ISP link, and yes is Point To Point link and
> talk with the guys that setup that router, but im thinking in put a
> freebsd box between our lan and the router and sniff all the traffic
> and see whats is happening but wich port to use...?

ntop can show how much bandwidth is used by whom
There are many available and I'm not sure ntop is the
best choice. There is pfSense which is a FreeBSD based
live-CD for router-like installations. pfSense has ntop
package. it won't hurt trying it out.

> , thanks all for 
> your help.
>
>    Ethereal is for read packets but can he check wich one device is
> causing problems..?

device causing problems? Do you mean computer using
a lot of bandwidth? You can check this with ntop(and a thousand
others I guess, use google)