> Source: [sk121673](https://support.checkpoint.com/results/sk/sk121673)

# sk121673 - What is the '2MSL' value?

| Property | Value |
|----------|-------|
| Solution ID | sk121673 |
| Date Created | 2017-11-27 |
| Last Modified | 2022-06-26 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Solution

The 2MSL (or 2 x MSL) timer refers to a 'timeout' value that is specified in RFC 793 (TCP) as part of the 'Closing' process of any TCP connection. A TCP connection may be in the 'Closing' state for 2MSL seconds before it is removed from the table (as per the RFC). The default MSL setting for any Linux kernel is 60 seconds, thus 2MSL (as per the RFC) would be 120 seconds. To confirm this value, use this command on any Linux system:

**# cat /proc/sys/net/ipv4/tcp_fin_timeout**

For Check Point Gateways, this setting is not used because of Stateful Inspection. The Stateful Inspection settings can be found in Global Properties in Smart Dashboard. In Stateful Inspection, you can change not only the 'TCP End' timeout but also many other timeouts related to TCP, UDP, and other protocols.

The default 'TCP End' timeout is 20 seconds.**\*** This means that the firewall allows a connection to remain in the connections table for 20 seconds (after having received 2 FIN packets, one from each side, or a RST packet). This allows for any stray ACKs of the connection that arrive late. Any other packets arriving after those 20 seconds is dropped as out-of-state. The 'TCP End' timeout value can be changed if required. However, changing it could have consequences such as idle connections that remain in the connections table for a longer than desired time. This fills the connections table's capacity quickly when many connections go through a gateway. Keep this mind before you make any changes to the "timeout" value.

**\* In R80.20 and higher versions, the default TCP END timeout value is 5 seconds.**

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