Many users think that the tcp_keepalive_time Linux OS setting is applicable for modifying/setting ipv4 parameters only (since it is accessed at /proc/sys/net/ipv4/tcp_keepalive_time). But as per Linux documentation from "kernel.org" website:

IPv6 has no global variables such as tcp_. tcp_ settings under ipv4/ also apply to IPv6

So, it will be appreciated that if an update is made in the documentation to state that the tcp_keepalive_time is applicable for ipv6 as well.