This method tries to connect to some TCP port that is unlikely to be filtered (e.g.

For computers, this method can actually sometimes work even better than ICMP Echo, because some administrators/firewalls tend to block ICMP Echo packets, but allow UDP packets to travel freely.

Some network devices (such as home routers) don’t implement UDP protocol at all and therefore appear as dead.

No response can mean that the UDP port is open (very unlikely) or the host is dead. If the packet is reseived, Angry IP Scanner knows that the host is actually alive and records the roundtrip time. If the port is closed, the host must send the ICMP packet back informing of the fact. The method works by sending out UDP packets to some UDP port very unlikely to be open. Angry IP Scanner will detect the absence of privileges and use this method automatically. This pinging method is preferred when you don’t have administrative privileges.

This should provide similar performance to pure ICMP Echo pinging on other platforms.

This is Windows-only pinging method to compensate for absence of Raw Sockets (see above).Īngry IP Scanner can now use the previously undocumented ICMP.DLL library to send ICMP Echo packets from Windows machines. However, starting with Windows XP SP2, Microsoft has removed Raw Socket support from consumer versions of Windows (Server editions still have them), so this method will not work on Windows anymore. If Angry IP Scanner runs without these privileges, this method can’t be used.Īngry IP Scanner implements this using the Raw Sockets. However, as it involves sending of ICMP (Internet Control Message Protocol) packets, it requires administrative (or root) privileges.

This is the same method used by the ping program. In the same place you can also select the pinging method. This behavior can be changed in the Preferences dialog, Scanning tab. Angry IP Scanner implements several different methods of detecting alive hosts (pinging).Īs a rule, if hosts don’t respond to pings, they are considered dead and therefore not scanned further.

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