About filters
Filters are used to isolate particular types of traffic on the network for troubleshooting, analysis, and diagnostics. If you want to check a problem between two particular devices, perhaps a computer and a printer, address filters can capture just the traffic between these two devices. If you are having a problem with a particular function on your network, a protocol filter can help you locate traffic related to that particular function.
Filters work by testing packets against the criteria specified in the filter. If the contents or attributes of a packet match the criteria specified in a filter, the packet is said to “match” the filter. You can build filters to test for just about anything found in a packet: addresses, protocols, patterns, ports, error conditions, and more.