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tshepang
tshepang
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So I can use this netcat command to check if a UDP port is open:

$  nc -vz -u 10.1.0.100 53
Connection to 10.1.0.100 53 port [udp/domain] succeeded!

Unlike TCP, UDP is connectionless (fire and forget). So at a high level does anyone know how netcat knows the UDP port is open? Does it ask for a reply or something like that?

Thanks!!

So I can use this netcat command to check if a UDP port is open:

$  nc -vz -u 10.1.0.100 53
Connection to 10.1.0.100 53 port [udp/domain] succeeded!

Unlike TCP, UDP is connectionless (fire and forget). So at a high level does anyone know how netcat knows the UDP port is open? Does it ask for a reply or something like that?

Thanks!!

So I can use this netcat command to check if a UDP port is open:

$  nc -vz -u 10.1.0.100 53
Connection to 10.1.0.100 53 port [udp/domain] succeeded!

Unlike TCP, UDP is connectionless (fire and forget). So at a high level does anyone know how netcat knows the UDP port is open? Does it ask for a reply or something like that?

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Patrick McMahon
Patrick McMahon
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How does netcat know if a UDP port is open?

So I can use this netcat command to check if a UDP port is open:

$  nc -vz -u 10.1.0.100 53
Connection to 10.1.0.100 53 port [udp/domain] succeeded!

Unlike TCP, UDP is connectionless (fire and forget). So at a high level does anyone know how netcat knows the UDP port is open? Does it ask for a reply or something like that?

Thanks!!