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Groups > linux.debian.user > #264237

Look, ma no telnet [was: Telnet]

From <tomas@tuxteam.de>
Newsgroups linux.debian.user
Subject Look, ma no telnet [was: Telnet]
Date 2023-12-04 20:00 +0100
Message-ID <HHmkF-b93X-1@gated-at.bofh.it> (permalink)
References (1 earlier) <HGGbL-aEsa-1@gated-at.bofh.it> <HGSwh-aM6O-1@gated-at.bofh.it> <HGXcB-aOYL-5@gated-at.bofh.it> <HGZR8-aQmS-7@gated-at.bofh.it> <HHcuZ-b17b-3@gated-at.bofh.it>
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On Mon, Dec 04, 2023 at 09:23:16AM +0100, Nicolas George wrote:
> Charles Curley (12023-12-03):
> > True. None the less, there is at least one perfectly good use for
> > telnet: testing connections to servers.
> 
> Wrong. The telnet client is not entirely transparent, as the telnet
> protocol defines an escape octet to introduce commands.
> 
> If you want to test a network protocol, you should use a really
> transparent client. Traditionally people use netcat (nc), but it handles
> EOF approximatively.
> 
> For that use, I strongly recommend socat.

These days, even bash can do it:

tomas@trotzki:~$ exec 3<>/dev/tcp/localhost/80
tomas@trotzki:~$ echo -ne "GET / HTTP/1.0\r\n\r\n" >&3
tomas@trotzki:~$ cat <&3
HTTP/1.0 200 OK
Content-Type: text/html
ETag: "3243577940"
Last-Modified: Mon, 30 Oct 2017 17:09:28 GMT
Content-Length: 3378
Connection: close
Date: Mon, 04 Dec 2023 18:55:37 GMT
Server: lighttpd/1.4.59

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>


These days, even bash can do it:

  tomas@trotzki:~$ exec 3<>/dev/tcp/localhost/80
  tomas@trotzki:~$ echo -ne "GET / HTTP/1.0\r\n\r\n" >&3
  tomas@trotzki:~$ cat <&3
  HTTP/1.0 200 OK
  Content-Type: text/html
  ETag: "3243577940"
  Last-Modified: Mon, 30 Oct 2017 17:09:28 GMT
  Content-Length: 3378
  Connection: close
  Date: Mon, 04 Dec 2023 18:55:37 GMT
  Server: lighttpd/1.4.59

  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml">
  <head>
  [... rest elided ...]

;-)

(alas, it can't do TCP server, which is a pity)

Cheers
-- 
t

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Thread

Telnet William Torrez Corea <willitc9888@gmail.com> - 2023-12-02 17:00 +0100
  Re: Telnet Marco Moock <mm@dorfdsl.de> - 2023-12-02 17:10 +0100
    Re: Telnet Greg Wooledge <greg@wooledge.org> - 2023-12-02 17:20 +0100
    Re: Telnet William Torrez Corea <willitc9888@gmail.com> - 2023-12-02 17:40 +0100
  Re: Telnet Andy Smith <andy@strugglers.net> - 2023-12-02 23:00 +0100
    Re: Telnet Michel Verdier <mv524@free.fr> - 2023-12-03 12:10 +0100
      Re: Telnet Marco Moock <mm@dorfdsl.de> - 2023-12-03 17:10 +0100
        Re: Telnet Charles Curley <charlescurley@charlescurley.com> - 2023-12-03 20:00 +0100
          Re: Telnet Greg Wooledge <greg@wooledge.org> - 2023-12-03 20:10 +0100
            Re: Telnet Charles Curley <charlescurley@charlescurley.com> - 2023-12-03 20:30 +0100
              Re: Telnet debian-user@howorth.org.uk - 2023-12-03 21:30 +0100
                Re: Telnet Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2023-12-04 11:30 +0100
                Re: Telnet gene heskett <gheskett@shentel.net> - 2023-12-04 12:40 +0100
                Re: Telnet debian-user@howorth.org.uk - 2023-12-04 17:20 +0100
                Re: Telnet Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2023-12-05 11:20 +0100
            Re: Telnet Tim Woodall <debianuser@woodall.me.uk> - 2023-12-04 11:40 +0100
              Re: Firefox, was: Telnet Michael Kjörling <2695bd53d63c@ewoof.net> - 2023-12-04 13:10 +0100
                Re: Firefox, was: Telnet Tim Woodall <debianuser@woodall.me.uk> - 2023-12-04 15:30 +0100
          Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 09:30 +0100
            Re: Telnet Marco Moock <mm@dorfdsl.de> - 2023-12-04 17:30 +0100
              Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 17:40 +0100
          Re: Telnet Marco Moock <mm@dorfdsl.de> - 2023-12-04 09:30 +0100
            Re: Telnet Curt <curty@free.fr> - 2023-12-04 17:30 +0100
              Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 17:40 +0100
                Re: Telnet Curt <curty@free.fr> - 2023-12-04 17:50 +0100
                Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 18:00 +0100
                Re: Telnet <tomas@tuxteam.de> - 2023-12-04 18:40 +0100
                Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 20:10 +0100
                Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 20:30 +0100
                Re: Telnet <tomas@tuxteam.de> - 2023-12-05 06:10 +0100
                Re: Telnet Nicolas George <george@nsup.org> - 2023-12-05 08:50 +0100
                Re: Telnet tomas@tuxteam.de - 2023-12-04 20:30 +0100
          Re: Telnet Nicolas George <george@nsup.org> - 2023-12-04 09:30 +0100
            Re: Telnet Nicholas Geovanis <nickgeovanis@gmail.com> - 2023-12-04 17:20 +0100
            Look, ma no telnet [was: Telnet] <tomas@tuxteam.de> - 2023-12-04 20:00 +0100
              Re: Look, ma no telnet [was: Telnet] <tomas@tuxteam.de> - 2023-12-04 20:10 +0100
              Re: Look, ma no telnet [was: Telnet] Nicolas George <george@nsup.org> - 2023-12-04 20:10 +0100

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