We have a Fortigate 600E, in which on latest couple of weeks we've been having a continuous problem with IPSec VPN users being disconnected very often (some within few minutes).
We've been making some testing and users on SSL VPN do not suffer from the same issue, SSL VPN is much more stable than IPSec. Sometimes we have some packet loss, but doesn't disconnect.
We have about 100 to 200 users on IPSec, and the Firewall capacity is far from being exhausted.
One thing I noted while testing, was that when I connect to the IPSec VPN, then connect to same server in my DC, and do a file copy, the VPN disconnect almost every time without finishing the copy correctly, so seems something stresses out the connection until it disconnects.
We're moving some users to SSL so they have more stability, but we're still blind to the root cause of the issue. Anyone experienced something similar and found the root cause?
Or is there any tests that I can try on the Firewall and on the endpoints to find the root cause?
Thanks in advance