Comment 4 for bug 1736804

The relevant commit that namespaces this file is:

commit 13b287e8d1cad951634389f85b8c9b816bd3bb1e
Author: Nikolay Borisov <email address hidden>
Date: Thu Jan 7 16:38:43 2016 +0200

    ipv4: Namespaceify tcp_keepalive_time sysctl knob

    Different net namespaces might have different requirements as to
    the keepalive time of tcp sockets. This might be required in cases
    where different firewall rules are in place which require tcp
    timeout sockets to be increased/decreased independently of the host.

    Signed-off-by: Nikolay Borisov <email address hidden>
    Signed-off-by: David S. Miller <email address hidden>