#Wireshark capture filter by port code
#Wireshark capture filter by port Pc
#Wireshark capture filter by port download

If the filter doesn't match, the packet never gets copied to wireshark's process space.

#Wireshark capture filter by port code

Wireshark uses a tool called WinPcap, a kernel module, which actually compiles your capture filters into native code at runtime to create an extremely optimized test for whether or not the capture filter is matching or not. 47 in HEX is 2F, so the capture filter for this is ip proto 0x2f.

#Wireshark capture filter by port Pc

On Windows anyway, the implementation of packet capturing occurs mostly on the kernel side. On your Sniffer PC running Wireshark, you’ll want to configure a Capture Filter that limits the captured traffic to IP Protocol number 47, which is GRE. Otherwise wireshark will introduce significant CPU load and I/O throughput. This is why, if you're wiresharking a very busy server just to observe one specific flow or process, it is essential to set reasonable capture filters. IIRC, Wireshark dumps its packet caps to disk (so it doesn't go OOM), so probably the bottleneck that occurs with 'too wide' capture filters is with your disk subsystem having to log everything going on on your network interface.

Clear the capture filter completely, and compare the performance and CPU usage in Step 3 to setting the same sort of filter on the display filter side. The same is true for 'tcp.port', 'udp.port', 'eth.addr', and others.

In the Capture Filter box type host 8.8.8.8. Double-click on the interface you want to use for the capture.

#Wireshark capture filter by port download

Capture on the localhost network interface with a capture filter that ignores the port where the huge download is taking place. To capture network traffic using a capture filter: Select either the Capture menu and then the Interfaces dialog box or the List the available capture interfaces toolbar button.Start an enormous HTTP file download (gigabytes of data).

Start up a fast web server on localhost.You can actually try this and feel the performance difference in the UI (and observe the performance difference in CPU usage) by doing something like this:

(My firewall is down and I try it by wirelles and copper.) What. This is useful for capturing unicast messages sent. The data never gets copied to wireshark if it fails to match the capture filters. Then on My wireshark Im using a filter udp.port 6666 to see the traffic but nothing happens. Port mirroring is the process of setting a port on a switch to output the same data as other ports. Wireshark has two types of filters: display filters, and capture filters.ĭisplay filters are more flexible than capture filters (there are some things that capture filters can't do) because display filters look at the data after it has already been copied over to wireshark's packet log.Ĭapture filters can be a huge benefit to performance if you have lots of separate flows of data going through your network interface, but you only want to capture a small amount of it.