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When macOS High Sierra (10.13) was released, the telnet
utility disappeared. This has probably been a good move by Apple since telnet
is outdated and not a secure protocol; it shouldn't be used in general. However, telnet
did serve a useful function - checking if it was possible to connect to a remote server on a particular port. Luckily there is a much better tool for this included in macOS - nc (netcat)
is simple and it has command line arguments that are very similar to telnet
. I like to use the -vz
arguments whenever I need to check if a remote server can be reached on a particular port. These arguments make nc
have this behaviour...
-v Have nc give more verbose output.
-z Specifies that nc should just scan for listening daemons, without sending any data to them.
The result is nc
tries to connect to the server and then immediately terminates if it succeeds. Here's an example...
If a connection cannot be established and a timeout is reached the output is like this (timeout can be controlled via the -G option i.e. -G 5
If a connection is refused, the output is like this...
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Although I put in a great effort into researching all the topics I cover, mistakes can happen.
If you spot something out of place, please do let me know.
All content and opinions expressed on this Blog are my own and do not represent the opinions of my employer (Oracle).
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