netstat -M works as expected until ICMP is masqed. Then, the result is: masq_info.c: Internal Error `ip_masquerade unknown type'. Per bugid #1154, netstat was built from net-tools-1.50-0.src.rpm. I'm running kernel 2.0.36-3.
the newer netstat commands expect kernel 2.2 masquerading/firewalling semantics. You can't use these newer packages without a 2.2 kernel. Please recompile the the 1.46 version that came with 5.2 to include masquerading support if you need it, or upgrade to a newer release of the kernel and use the 1.5x version from 6.0 or RawHide.