3. IPv6-related entries in /proc/sys/net/ipv4/

At the moment (and this will be until IPv4 is completly converted to an independend kernel module) some switches are also used here for IPv6.

3.1. ip_*

3.1.1. ip_local_port_range

This control setting is used by IPv6 also.

3.2. tcp_*

This control settings are used by IPv6 also.

3.3. icmp_*

This control settings are not used by IPv6. To enable ICMPv6 rate limiting (which is very recommended because of the capability of ICMPv6 storms) netfilter-v6 rules must be used.

3.4. others

Unknown, but probably not used by IPv6.