This works with TCP because IO::Socket::INET->new() calls connect() in that case which does a SYN/ACK handshake to open a connection. The handshake fails if the port is not open.

UDP is a connectionless protocol so nothing happens on the network until you try to send some packets to the peer. Creating the socket will succeed whether the remote port is open or not.

In reply to Re: IO::Socket::INET issues? by jdalbec
in thread IO::Socket::INET issues? by Anonymous Monk

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