Technical Tip: FortiGate fails to generate statistic traffic logs

[cravikumar]

Description	This article describes why no statistic traffic logs are generated on the FortiGate even though sessions are established.
Scope	FortiGate.
Solution	By design, FortiGate generates a log every 2 minutes for new/existing sessions. However, the 2-minute interval is packet-driven. Every time a packet flows through the session, the FortiGate checks if 2 minutes have elapsed. If this is the case, a log is generated and if there is no traffic for an extended period, no statistical log will be generated. For example: When a user browses a webpage and stops interacting, a log is generated after the first 2 minutes, but no further logs appear unless traffic resumes. If the 'logtraffic-start' option is enabled on the policy, the new session log will show up immediately whereas the existing session log may take up to 2 minutes. Below is the command snap. On v7.0.x or previous OS versions, the setting can be enabled via GUI, as per the picture below: Related article: Technical Tip: How to know the starting time of a traffic session