Jump to Navigation

084 - Change DHCP to Static IP Address.

When you change your network configuration (IP Address), There are two ways ("setup command" or change related files manually)
to do that. setup command might be easy for change, but you want to know how to change it manually.

1. Login a Linux Server as root.

2. Check your IP address using ifconfig command.

[myserver]# ifconfig

083 - MySQL Error 1130 "Host is not allowed to connect ...

Error 1130 is a networking error. The server cannot resolve the hostname of the client. Or the host is not allowed to connect to the MySQL server.

First you should check a user in the remort server in order to login, If not there, You have to create a user for remote login.

mysql> use mysql;
mysql> select host, user from user;

There is no your host name, the following command can create user.

082 - MySQL Slave ERROR 1201

If you get the following error, You should recreate a slave database.
It might be easy to fix the problem.

1. Stop slave

mysql> stop slave;

2. Delete files

mysql-relay-bin.000000x, mysql-relay-bin.index



081 - Creating aliases and mail redirects

A simplest way to redirect mail (either from users who don't exist, or from users who do exist) is with the /etc/aliases file.
The format is pretty simple:

080 - Use Mail command

The Mail utility allows you to compose, send, receive, forward, and reply to mail. mail has two main modes: compose mode, in which you create
a message, and command mode, in which you manage your mail.

You can also provide much of the information on the command line, as shown in the following example:

[MyServer]# mail james -s "System Log" < /var/log/messages

If you want to send the user outside of the server.


079 - How to SSH without password

Secure Shell is a program to log into another computer over a network, to execute commands in a remote machine, and to move files from one machine
to another. It provides strong authentication and secure communications over insecure channels. It is a replacement for rlogin, rsh, rcp, and rdist.
SSH protects a network from attacks such as IP spoofing, IP source routing, and DNS spoofing. An attacker who has managed to take over a network
can only force ssh to disconnect. He or she cannot play back the traffic or hijack the connection when encryption is enabled.


078 - Using chkconfig to change runlevel

The chkconfig command can also be used to activate and deactivate services. If you use the chkconfig --list  command, you will see a list of system services
and whether they are started (on) or stopped (off) in runlevels 0-6 (at the end of the list, you will see a section for the services managed by xinetd.

If you use chkconfig --list to query a service managed by xinetd, you will see whether the xinetd service is enabled (on) or disabled (off). For example,
the following command shows that finger is enabled as an xinetd service:


077 - About runlevel

runlevel is a preset operating state on a Unix-like operating system.

A system can be booted into (i.e., started up into) any of several runlevels, each of which is represented by a single digit integer.
Each runlevel designates a different system configuration and allows access to a different combination of processes
(i.e., instances of executing programs). The are differences in the runlevels according to the operating system.
Seven runlevels are supported in the standard Linux kernel (i.e., core of the operating system).

They are:

076 - Installation of webmin

  • What is webmin?

Webmin is a web-based interface for system administration for Linux. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Linux configuration files like /etc/passwd, and lets you manage a system from the console or remotely.

  • Installing RPM

If you are using the RPM version of Webmin, first download the file and then run the command :

075 - blowfish_secret error

After installation of  phpMyAdmin, maybe you get the following error.

The configuration file now needs a secret passphrase (blowfish_secret).

To solve it, you could edite the phpmyadmin/config.inc.php file.
simply find the $cfg['blowfish_secret']= "" and input your blowfish secret from the file you found inside the "".
then comment out the include /etc/phpmyadmin/blowfish_secret.inc.php line and you should be ready to go.



Subscribe to LAMP, Database and Cloud Technical Information RSS

Main menu 2

by Dr. Radut