I am using telnet on windows 10. I would like to manually set get requests to chosen server.

If I type (just example it can be any site):

telnet www.cnn.com 80

for a second I see message 'connecting to www.cnn.com'. Text on the page then disappears (nothing is shown, just cursor). Whatever I try to type, message of 'bad request' is immediately shown from the server.

Why is that? Why - after connection is established with server - is this not shown? Something like 'connected to www.cnn.com' and telnet commands enabled?

  • telnet www.cnn.com 80 works as expected when I try it (and as you mentioned, this is just an example). Perhaps you have an outbound firewall that is doing packet inspection and realises that something is wrong (i.e. attempting to run non-HTTP over the HTTP port) – Mark Henderson Dec 3 at 5:53
  • I've turned off firewall and also added exception to firewall but it's the same. It seems like connection is established I just can't see what I type. And whatever I type after pressing enter I am receiving errors. – FrenkyB Dec 4 at 0:42

telnet does not support SSL connection. Please test against a URI/address that does not redirect to HTTPS

Edited; As stated in comment, Mark is right too, you should see a HTTP 301 redirect in telnet in the bare minimum, so it can be a local antivirus that scan your network traffic that block the traffic, or the router that do DPI.

  • Why is there no warning or anything? Just black screen. – FrenkyB Dec 3 at 4:07
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    Not sure this is true. Telnet is opening a socket to port 80, but the redirect to HTTPS (port 443) should not happen until after a request has been issued (i.e. a GET) – Mark Henderson Dec 3 at 5:50
  • @MarkHenderson You are right, the user would see a HTTP redirect 301 before it goes blank, edited to reflect it – yagmoth555 - GoFundMe Monica Dec 3 at 13:27
  • No, they really shouldn't. A redirect isn't given until a valid HTTP request is made (if a redirect is given at all). Telnet clears the screen on successful connection, and since the other side doesn't send anything (as per the HTTP protocol requirements, it is the client who sends the first command), the screen remains black. Since local echo is disabled by default, and the other side doesn't echo your data, you don't see what you type either. – Lacek Dec 3 at 14:28
  1. Check whether your telnet client service has been activated, if else you have to turn on the telnet client feature on your windows 10.
  2. once it is turn on it will restart the PC.
  3. Then you can use your telnet commands.
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    OP reports using Telnet so we can assume it is installed – Dave M Dec 3 at 16:26
  • Exactly as @DaveM said. – FrenkyB Dec 4 at 0:28

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