vurmakers.blogg.se - How to use wireshark to troubleshoot slow lan

The tcpdump command line is a utility that allows you to capture and analyze network traffic going through your system.

Data display can be refined using a display filter.

Captured files can be programmatically edited or converted via command-line switches to the "editcap" program.

Captured network data can be browsed via a GUI, or via the terminal (command line) version of the utility, TShark.

Live data can be read from different types of networks, including Ethernet, IEEE 802.11, PPP, and loopback.

Data can be captured "from the wire" from a live network connection or read from a file of already-captured packets.

Wireshark uses pcap to capture packets, so it can only capture packets on the types of networks that pcap supports.

Since Wireshark is a data capturing program that "understands" the structure (encapsulation) of different networking protocols, it can parse and display the fields along with their meanings as specified by different networking protocols. Simple passive taps are extremely resistant to tampering Port mirroring or various network taps extend capture to any point on the network. However, when capturing with a packet analyzer in promiscuous mode on a port on a network switch, not all traffic through the switch is necessarily sent to the port where the capture is done, so capturing in promiscuous mode is not necessarily sufficient to see all network traffic.

Wireshark lets the user put network interface controllers into promiscuous mode (if supported by the network interface controller), so they can see all the traffic visible on that interface, including unicast traffic not sent to that network interface controller's MAC address. It is very similar to tcpdump, but has a graphical front-end, plus some integrated sorting and filtering options. Wireshark is a free and open-source packet analyzer used for network troubleshooting, analysis, software and communications protocol development, and education.