A session is a communication channel between two devices or applications across the network. Sessions allow FortiOS to inspect and act on a sequential group of packets in a session all at once instead of inspecting each packet individually. Each session has an entry in the session table that includes important information about the session.
You can view FortiGate session tables from the FortiGate GUI or CLI. The most useful troubleshooting data comes from the CLI. The session table in the GUI also provides useful summary information, particularly the current policy number that the session is using.
Session tables are useful when verifying open connections. For example, if you have a web browser open to browse the Fortinet website, you would expect a session entry from your computer on port 80 to the IP address for the Fortinet website.
You can also use a session table to investigate why there are too many sessions for FortiOS to process.
- Go to Security Fabric > Physical Topology.
- From the Metrics dropdown, select Sessions.
Every program and device on your network must have an open communication channel or session to pass information. FortiGate manages these sessions with features such as traffic shaping, antivirus scanning, and blocking known bad websites. Each session will have an entry in the session table.
If a secure web browser session is not working properly, you can check the session table to ensure the session is still active and going to the proper address. The session table can also tell you the security policy number it matches, so you can check what is happening in that policy.