By: Ranjan S. Chari
Note: Most commands here would require you to have a superuser status.
To see what services are running on your system
# chkconfig --list
By default this file is located in your /sbin directory.
# netstat -a | grep LISTEN
This will give you a list of all listening devices.
To shutdown uneeded services so that no service sits around listening to ports when it's not required
Assuming that xinetd is running on your system and controls the startup of a relevant service when it's requested:
Look at the directory:
The directory contains files which are configuration file for services that the xinetd daemon controls.
Let's say you want to turn telnet off.
Examine the telnet file.
You see something like so:
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/sbin/in.telnetd
log_on_failure += USERID
disable = no
replace the second last line disable=no with disable=yes
You'll require a xinetd restart. So go to the directory that contains the xinetd daemon.
# cd /etc/rc.d/init.d/
And restart the application:
To create your custom telnet welcome message:
Edit the file /etc/issue.net
Place your own custom message.
The next time someone telnets in, he/she'll get that message.
To figure out which Redhat version you are using
#rpm -q redhat-release
To diable guest and anonymous FTP access to your Redhat server if using WuFTPd
Edit the file: /etc/ftpaccess
From the line:
# User classes...
Remove guest and anonymous.
To change your IP Address
Edit the file:
To make applications load up at bootup
Edit the file:
Add in the command to load up your application at the very end of the file.
To list IP address for all devices on the machine
Finding an IP address of a Hostname