Telnet command missing

It's not you.

Cool - thought I may have had a dodgy install or something.

Strange thing to leave out - they must have had a reason? Hopefully it will be back in a next release as it's a good diagnostic tool to use.

Hmm. telnet and ftp (also not present in 10.13 Beta) are insecure. Use ssh and sftp instead.

Of course they are insecure, but sometimes you have no other choice but to use them. This command better returns, otherwise I am forced to install Windows/Linux...

You can't use ssh to connect to port 25 to test a SMTP server, POP3 server, or check if a port is open at the destination..

telnet is an incredibly useful diagnostic and debug tool .... I use it at some point nearly every day diagnosing SMTP connection problems, accessing old Cisco switches / routers on my internal private/secure network, connecting to serial consoles across a local/private network and more.

As a network engineer it is pretty much an essential tool (as is the escape key on a keyboard and to a lesser extent the function keys)

Apple don't seem to be considering us "technical" users when they make changes .... I hope they're readying this and re-consider

One of the things stopping me upgrading to a new MacBook Pro with Touch Bar (at a cost of about $5k) is because it doesn't have an easily accessible escape key (silly I know) ... removing telnet/ftp/etc from the OS is going to stop me upgrading

Worse still, I might have to look at moving back to Linux / OpenBSD for my $dayjob ...

Apple, please consider the Pro users when you try to "improve" things. It was bad enough when you removed PPTP from iOS ... it may be flawed, but it was better than nothing - and now we're less secure as we have to use an unencrypted connection because L2TP isn't a viable option.

There's being "brave" (god I miss the headphone jack) and there's being stupid for the sake of it / headlines 😟

Can't you simply use nc ?

A quick google shows this is probably the way going forward:

http://www.terminalinflection.com/use-netcat-not-telnet-to-test-network-connectivity/

If you really need it: Install MacPorts <https://www.macports.org> and grab inetutils from my branch

https://github.com/Schamschula/macports/blob/master/net/inetutils/Portfile

This gives you all the standard network daemons and clients.

Sorry if I'm blunt, but if you are a "technical" user who "might have to look at moving back to Linux / OpenBSD for my $dayjob" you should, at the very least, knew that netcat (nc) exists and that you can very well use it to accomplish the same things.

I agree with you that opening terminal and typing "telnet" is ingrained in our minds and as such, is the very first thing we'd do. As a matter of fact, I did, and that's how i noticed that the telnet program went the way of the Dodo in 10.13 dev beta, but the network engineer (hacker?) in me kicked in and I switched to nc, where I finished the SMTP diagnostic I was going to do.

I was a Network Engineer before moving on to network and nformation security and I understand why the bold move was done and, as a matter of fact, i encourage it. You should see the things one sees when working on security.

It's inconvenient, yes, but there are workarounds if you know what you're doing, and if you really need to use legacy (read: insecure) tech.

You can copy Telnet over from a Seirra machine by jumping through a few hoops. I use Telnet all the time; filed a suggestion on Bugreporter to put it back. I agree with jmorby completely.

Agree with jmorby as well. You can't use SSH until you telnet into a Cisco router/switch and generate the encryption keys. The other option is to use a USB-to-Serial adapter and use the console port and a terminal emulator. Of course, telnet/ftp are not secure until you can get in the device and configure it for usernames/passwords/SSH/sftp.

BTW - It would be nice if Apple would enhance Terminal to enable a ZTerm/PuTTY type virtual serial port for accessing Cisco devices and other consoles that don't have ethernet/IP.

any suggestions why i cannot copy the telnet application to /usr/bin

Operation not permitted

Telnet is removed in high sierra due to its a 32bit program 😐. I use ssh now.

if I could i would but we have system they are using telnet

i used the workaround from @John daniel

https://forums.developer.apple.com/message/235897#235897