Network Traffic

[mattianuk]

Hi

 

Whats the best way to monitor traffic on the network? I can see from our county broadband box we are maxing out our 10mb connection, but even with smoothwall I am struggling to see why - I want to monitor traffic to identify if its say chrome updates, or general usage.

 

I also want to be able to monitor the impact of having 50IP cameras on a flat network with no VLANs - I spoke to a chap from the switch shop at BETT who straight away said I need VLANs, but I would like some physical proof of this - and also just to be nosey of traffic levels etc

 

We have allied tenison switches, some HP, some netgear, so a real mismash.

 

Cheers

[jamesfed]

I use PRTG to monitor my internal network traffic flow, you could point the sFlow sensor at your core switch which would then map out what protocols are flowing from where to where (including your Smoothwall server).

[SYNACK]

Well without any special switch involvement you can use something like Wireshark Wireshark · Go Deep. or MS Network Moniter Download Microsoft Network Monitor 3.4 from Official Microsoft Download Center which will let you snoop on the broadcasts. In order to do this for specific links like your internet one you would need to set up the switch to mirror the port (can slow the switch down) to your sniffer or put in a hub between the switch and your target then connect your sniffer to that (not recommended as it will slow stuff down). You can also look at using network monitering stuff like theDude to moniter port and cpu usage on your switches MikroTik Routers and Wireless: The Dude assuming they support snmp.

 

Be aware that traffic snooping like this can be very invasive when monitering an internet link so you may need permission as you could easily come across unencrypted passwords for websites etc.

 

The biggest thing that VLANs would help with is broadcast traffic so I'd start with wireshark on a standard network interface and see how much broadcast traffic there is flying about. Remember that broadcast packets have to be picked up and inspected by every single network card and resent to all ports by all switches so they can effect CPU usage on switches and even devices, especially smaller ones like network printers etc. Stuff like Bonjour is a reall nightmare that will spew rubbish all day long, fine on small network segments but nasty on a large segment.