Restrict remote telnet connection + port 80

minim · 05-05-2011, 11:00 AM

Hello,

Is it possible to restrict telnet connection from remote to my server(linux -centos5)?

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Ex : [root@localhost]# telnet 10.0.0.33 80
Trying 10.0.0.33...
Connected to 10.0.0.33 (10.0.0.33).
Escape character is '^]'.

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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Telnet server is not running in my server. And we have a site running at port 80. Is it possible that remote system should not use telnet to check the port 80 to my server?

And more that is there any possibility that remote system can attack via telnet using port 80?

Thanks in advance

Minim

druuna · 05-05-2011, 11:32 AM

Hi,

Quote:

Is it possible to restrict telnet connection from remote to my server

Too my knowledge you cannot protect a listening port (80 in this case) to answer if telnet (or any other service) tries to connect to it. Iptables, for example, sees this as a normal request (which it is: somebody knocked on door number 80).

Quote:

And more that is there any possibility that remote system can attack via telnet using port 80

Possible? Yes! But it does depend on how well apache (or equivalent) is set up. If it is securely set up the chance of this happening is very small. The possibility of attack will not be larger or smaller if you would be able to disallow telnet access.

Hope this helps.

minim · 05-05-2011, 12:04 PM

Quote:

Originally Posted by druuna

Hi,

Too my knowledge you cannot protect a listening port (80 in this case) to answer if telnet (or any other service) tries to connect to it. Iptables, for example, sees this as a normal request (which it is: somebody knocked on door number 80).

Thanks for responding

Helpful information.