I'm working on a Linux network deice, and there are some TCP/IP settings that don't seem to have IPv6 equivalents. IP forwarding is a common setting, and available in both stacks
But these are examples of some setting I would need to support IPv6
net.ipv4.ip_nonlocal_bind net.ipv4.ip_local_port_range net.ipv4.tcp_tw_reuse net.ipv4.tcp_rmem net.ipv4.tcp_wmem
ip_nonlocal_bind is pretty critical, and settings for TCP TIME_WAIT sockets are seemingly missing.
Pointers to kernel/iproute documentation which I may have missed would be great too.