Nessus SYN scanner
Info Nessus Plugin ID 11219
SynopsisIt is possible to determine which TCP ports are open.
DescriptionThis plugin is a SYN 'half-open' port scanner. It shall be reasonably quick even against a firewalled target.
Note that SYN scans are less intrusive than TCP (full connect) scans against broken services, but they might cause problems for less robust firewalls and also leave unclosed connections on the remote target, if the network is loaded.
SolutionProtect your target with an IP filter.