Changing the SSH Port Number
To change the SSH port number login as root, and edit /etc/ssh/sshd_config
Find the line that says Port 22 and change 22 to any number between 1024->65535 (above 30000 is best) and save the file.
Once done, run:
Now start a new SSH session (don’t close your existing one), to make sure that you can get in.
-p port
Port to connect to on the remote host. This can be specified on a per-host basis in the configuration file.
Enable Alternate Port other than 25 or 587 (via SSH) in Plesk
Make a copy of /etc/xinetd.d/smtp_psa. For this walkthrough the new filename created is smtp_nonstandard. A command like this should work:
cp /etc/xinetd.d/smtp_psa /etc/xinetd.d/smtp_nonstandard
Add these lines to the copy you just made:
vi /etc/xinetd.d/smtp_nonstandard
type = UNLISTED
port = 2525
and change the service name to match the name of the file. A sample smtp_nonstandard looks like this:
service = smtp_nonstandard
type = UNLISTED
socket_type = stream
protocol = tcp
port = 2525
wait = no
disable = no
user = root
instances = UNLIMITED
server = /var/qmail/bin/tcp-env
server_args = -Rt0 /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true
# Restart xinetd:
/etc/init.d/xinetd restart
# You should now be able to send mail through your server on port 2525. You may pick a different port if you use this method. We suggest choosing a high port number to avoid using commonly used ports on the internet.
How to change default 19368 port of control panel interface.
To change default 19638 port it is enough to change it in /etc/ensim/epl.conf file and restart epld service. In other configuration files it will be substituted accordingly.
Note that the sites configuration files are located in /etc/httpd/conf/virtual/ and include “RedirectMatch” directive that contain redirect to 19638 port.
Get exim to listen on another port other than 25
Some ISP’s are now blocking outgoing port 25 which prevents user from using smtp via their server. The workaround is to get exim to listen on another port other than 25 to bypass the ISP’s block.
For example, to get exim to listen on both port 25 and port 587, you’d add the following code to the very top of the /etc/exim.conf file:
daemon_smtp_ports = 25 : 587
Once saved, restart exim:
Redhat:
/sbin/service exim restart
FreeBSD:
/usr/local/etc/rc.d/exim restart
More: http://www.exim.org/exim-html-4.40/doc/html/spec_13.html#SECT13.5
How to check if the port is associated with the official list of known services.
Example:
cat /etc/services | grep 834
This command returns no output. This indicates that while the port is in the reserved range (meaning 0 through 1023) and requires root access to open, it is not associated with a known service.
Next, check for information about the port using netstat or lsof. To check for port 834 using netstat, use the following command:
The lsof command reveals similar information since it is also capable of linking open ports to services:
These tools reveal a great deal about the status of the services running on a machine. These tools are flexible and can provide a wealth of information about network services and configuration. Consulting the man pages for lsof, netstat, nmap, and services is therefore highly recommended.
