Connection tracking timeout

configname: CONFIG_NF_CONNTRACK_TIMEOUT

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>Core Netfilter Configuration
└─>Connection tracking timeout
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This option enables support for connection tracking timeout
extension. This allows you to attach timeout policies to flow
via the CT target.

If unsure, say `N'.