A normal Linux OS has a maximum of 65536 conntrack sessions by default, these sessions all require memory which is used by the host node & not by the VPS so using this limit too high can impact the whole node & allow users to use more RAM than their VPS has allocated by eating up the host’s RAM.
A typical VPS should never use more than 10000 sessions at any given time although we do have some busy servers that peak at 20000 once in a while.
If your VPS is using more then 10000 Conntrack sessions, its means there must be something wrong under your VPS. So you have to investigate it. There may be any abuse script is running or you may be under attack.
To check your conntrack sessions, run the following command in your VPS: