Windows: both 0 (no ICMP rate limiting — matches real Windows behavior)
Linux: 1000ms / mask 6168 (kernel defaults)
BSD: 250ms / mask 6168 (FreeBSD default is faster than Linux)
Embedded/Cisco: both 0 (most firmware doesn't rate-limit ICMP)
These affect nmap's IE and U1 probe groups which measure ICMP error
response timing to closed UDP ports. Windows responds to all probes
instantly while Linux throttles to ~1/sec.
Tests: 10 new cases (5 per sysctl). Suite: 822 passed.