max number of sessions

[claudiotesta]

Hi,

We're encountering session limits well before reaching CPU or memory capacity constraints. What could be restricting the number of concurrent sessions if neither CPU nor memory is the bottleneck? Could it be Linux limitations, database constraints, or limitations within the database engine? We're facing situations where a significant number of users consume minimal bandwidth, yet our firewall is struggling to keep up. For instance, managing 75,000 students accessing the internet poses a challenge.

How can we address this limitation without resorting to purchasing oversized appliances that would remain underutilized in terms of CPU and memory resources?

[spoojary]

You can check this forum: https://community.fortinet.com/t5/Support-Forum/High-current-session-leads-to-high-CPU-and-causes-in...

[AEK]

Hi Claudio

I may not have the full answer but I thing you should first try find which type of sessions are the highest number, then you may understand the root cause, then find a way to deal with these sessions.

Like once we noticed that our high-end firewall reached about 40% of its session number limit, then after analysis we found that more than almost 80% of them are DNS sessions, generated by clients but not useful. So we did two things to fix this issue: reduce TTL of DNS sessions, and remediate at client level to eliminate these unwanted DNS queries.

However each case has its special treatment. For now just try to understand what is consuming your sessions and why.