>However, I'm going to be using a networking analyzer like 'Capsa' (anybody used that?) to monitor the network.
No, but like any other sniffer I am sure it will get the job done; typically, the most popular sniffer I know of is wireshark. Sniffers will get you information you need to diagnose some networking issues, like too many requests, syn requests, type of packets are one your network, etc.
>We seem to have the network bottlenecking now and then. I think it could be down to the fact that our upload speeds aren't great.
Depending on what type of switch you have on your network and if it has SNMP capabilities, it might be a good idea to use cacti (
http://www.cacti.net/) and graph all switchports; this might at least give you an idea what host(s) are taking up the bandwidth, or it could be related to UDP based attacks that eat up your bandwidth. You might also want to look into if your switch supports a SPAN (mirror) session to you can use your sniffer more productively.
Billy
