Nmap NSE net: firewalk

Tries to discover firewall rules using an IP TTL expiration technique known as firewalking. The scan requires a firewall or 'gateway' and a metric or 'target'. For each filtered port on the target, send a probe with an IP TTL one greater than the number of hops to the gateway. The TTL can be give...

firewalk NSE Script

Tries to discover firewall rules using an IP TTL expiration technique known as firewalking. To determine a rule on a given gateway, the scanner sends a probe to a metric located behind the gateway, with a TTL one higher than the gateway. If the probe is forwarded by the gateway, then we can expec...