port blocking

Posted on 2001-06-19
Last Modified: 2010-03-18
How to block a particular (software) port and how to see what ports are blocked?  I am using Redhat 6.2 Linux.
Question by:narayanamoorthy
LVL 40

Expert Comment

ID: 6210365
ipchains comes readily to mind if you want to selectively block access to a given port. If you don't use the port and don't want anyone else to you can simply prevent the port from being accessed by disabling server for the port and/or preventing it from being started by inetd (check inetd.conf).

Expert Comment

ID: 6211487
You can see various services using the command ps -A and see that certain demeons are running the good way to block or stop that service use the inetd.conf file mostly places in /etc/inetd.conf and put a # in front on the line which you dont whant to use.


Expert Comment

ID: 6211805
'ps -aux' will give you a more detailed ideal of what is actually running on your system

Accepted Solution

fauzdar earned 10 total points
ID: 6213792
the best way to know what ports are blocked is to see what ports are open. for checking the open ports on you machine use nmap. its a easy utility to use. it tells you what all ports are open.

Expert Comment

ID: 6232307
Linux# ipchains -L -n

use linuxconf's firewall to block ports.


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