Technical Tip: Changing the TCP session TTL

[naveenk]

Description
This article describes how to change the session TTL Value using CLI for the idle TCP sessions.

Solution
When the TTL limit is reached, the session is dropped.
 
On FortiGate this is configurable under each firewall policy.
By default each session uses the default TTL value in system wide session-ttl setting.

# Config firewall policy
    edit <policyID>
        set session-ttl <value>                        <----- Enter an integer value from <300> to <2764800> or (special = <0>).
end

The default TTL value can be configured as shown below.

# config system session-ttl
    set default <value>        
    <integer>                                 <----- Value range (300 - 2764800).
end