/etc/services - is used to map ports and service-names to protocols, such as -  telnet 23/tcp

The name "telnet" is then referenced on /etc/inetd.conf which would then map these "service-names" to corresponding server that would get spawned(binary executable). If you are on a centos, check for xinetd.

I havent tried this, but may be you could try this, make the service names different on /etc/services - e.g. ssh_test 22/tcp , and run ssh using inetd/xinetd. You might be getting warnings or errors starting the service since it would reference a name "ssh" as the service name which wouldnot have any port/protocol associated on /etc/services?


On Tue, Jan 4, 2011 at 12:52 PM, keith smith <klsmith2020@yahoo.com> wrote:


Hi,

I'm working on several CentOS and one RHEL servers.  I needed to open a port the other day so I did a search and the info I found lead me to believe the only way to open or close a port was via iptables.  Is that the complete story?

For example, if I want to open port 3306 for MySql I need two things?  1) The port needs to be listed in /etc/services (RedHat) and 2) the port needs to be opened via iptables.

If I use a non-standard port (3306) I must add a line to the /etc/my.conf that defines the port such as "port=xxxx".

Here is a twist.  I set my SSHD to port 2200 but did not change /etc/services, which lists ici on port 2200 for both tcp and udp.  I am able to shell in using port 2200.  Why no conflict?

Thank you for your insight.



------------------------
Keith Smith


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