Javascript telnet client

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drgrussell
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Javascript telnet client

Post by drgrussell » Thu Aug 18, 2005 10:16 am

OK, so I was bored and got to thinking about all the users with broken proxying software. Right now, telnet and ssh users have their own IP detected from their http requests. This mechanism is easily misconfigured (perhaps by an admin who wants to disguise IPs).

So I have written a javascript program which gives the user a telnet client. As this runs using standard http request technology, it should run on any machine which has cookies and javascript switched on. OK, so the idea is a little stupid, and the performance is not as good as a real client, but it is surprisingly usable. I will add it into the connect tab of the management box at some point over the next few days.

It uses iframes to communicate, so it should run on a huge range of browsers. Let me know if you have any queries.

Enjoy.
G.

drgrussell
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Posts: 426
Joined: Sat Feb 12, 2005 8:57 pm
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Post by drgrussell » Tue Aug 23, 2005 6:17 pm

Javascript client is now available in the connect tab of the control frame.
It works but I still prefer a real telnet (which works too but it much faster).

This client may be the only way to connect for some users. Users who share a single IP (for instance behind a NAT firewall) enter a special mode when there is more than 1 simultaneous user. This mode asks users for their virtual machine IP number, but this interrupts the normal DO/DONT/CAN/CANT handshake of telnet. Window's clients dont mind this handshake occurring after text has been sent, but other clients fail to handle this and ignore the handshake requests. Unfortunately this hangs the telnet server in the virtual machines, and the connection hangs.

The long-term solution is to fix the handshake using some sort of handshake-proxy-thing. Short term fix is to use the javascript telnet client if your telnet seems to hang.

drgrussell
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Posts: 426
Joined: Sat Feb 12, 2005 8:57 pm
Are you a robot or a human?: Human

Post by drgrussell » Wed Aug 31, 2005 11:48 am

Having spent some time studying the rfc's for telnet, I am not sure there was a problem after all. Thus if your telnet does not work on the site, you should use the javascript telnet instead. Telnet not working due to proxy error can only happen in shared ip mode, which is rare anyway.

Basically, if telnet does not seem to connect you, it is much more likely that your virtual machine has not yet booted up or you are suffering some sort of user-induced error.

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