eNet Solutions - Internet and E-Mail Communication Specialists

	LOGGING IN		ADDING NEW USERS
	CHANGING PASSWORDS		DELETING USERS
	CHANGING USER PASSWORDS		MANUAL SEND / RECEIVE
	ADDING ALIAS ACCOUNTS		HOW TO SHUT DOWN
	CHECKING MAIL QUEUE		SPECIFIC COMMANDS
	CHECKING IF SQUID IS RUNNING		BASIC TROUBLESHOOTING
	CHANGE DIALUP NUMBERS		HOWTO RESET DATE AND TIME

LOGGING IN :

At the mail login prompt you type the user name:

root [ENTER]

Then it will ask for the password. Type the password then [ENTER]. You will then be logged into the machine and have a prompt similar to this:

[root@mail root]#

CHANGING PASSWORDS :

Changing the root password is not recommended, therefore, please contact us if for any reason you have to do so. Please do not try and change this password as if you forget this password it will be difficult for you to log into the system.

TO CHANGE A USER ACCOUNT PASSWORD :

passwd username [ENTER]

The system will ask you to enter the new password, and then enter it again to verify it.

ADDING ALIAS ACCOUNTS TO SERVER :

An alias account is an account which is created for Companies who would like a single email address for a particular department, for example, the Accounts Department might have one email address [accounts@domain.co.zw] or the Customer Support Department might have [support@domain.co.zw] The mail for this account will be directed to anyone in the Accounts department or Customer support department.

cd /etc [ENTER]

vi aliases [ENTER]

press [INSERT] on keyboard to go into edit mode. Use the arrow keys to scroll to the bottom. insert alias at bottom of file. Format is as follows:

alias: [TAB] usernames [SEPARATED BY COMMA]

to save: press [ESC] twice, press the colon key : press x [ENTER] then run the command

newaliases [ENTER]

CHECKING OUTGOING MAIL QUEUE :

mailq [ENTER]

This will show any mail waiting to be sent at the next dial-up.

HOW TO CHECK IF SQUID IS RUNNING :

SQUID is a Linux service which allows clients to browse the Internet. This service sometimes stops running, if you cannot browse the Internet the following steps should be taken to check this service is running.

ps ax [ENTER]

Check you can see:

/usr/local/squid/sbin/squid -D or Squid -D

If the Squid service is not running, you can start it by running this command:

service squid start

ADDING A NEW USER TO THE SERVER :

useradd username

passwd username

userdel -r username

DELETING A USER FROM THE SERVER :

DOING A MANUAL SEND/RECEIVE :

/etc/ppp/syncmail [ENTER]

This command forces the server to send and receive.

HOW TO SHUT DOWN THE SERVER :

You would only need to shut down the server in the event of a long power cut. If your UPS power starts to run low or start beeping faster, it is advisable to shut down the server properly

halt [ENTER]

Wait for it to tell you Power Down System.

SPECIFIC COMMANDS :

ls - lists the contents of the current directory you are in. Same as the DIR command on Windows machines.

cd - change directory command. Syntax is:

cd [SPACE] /nameofdirectory

ping - Very good troubleshooting tool, to check the state of your network connection. If you cannot ping a certain machine, check your network. Syntax is:

ping [SPACE] IP address of machine

df - shows the amount of hard drive space left. If the machine runs low on space it causes obvious problems. If your users are having problems with collecting email, this could be the reason.

ps ax - list all the processes running on the server. Good for troubleshooting, or to check if a particular program is running

nmap - port sniffing tool, used to check which ports are Open on a particular machine. Good for checking security of your server at a glance.May not be installed on older systems.Syntax is:

nmap [SPACE] name or IP of machine


CHANGING DIALUP NUMBERS :
How to change the dial in number Sometimes your server fails to connect to your ISP because the particular number you are dialing is having problems. This is usually the case if you do not hear the "handshake" after dialing. Changing the phone number may solve the problem. Find out from your ISP what other numbers you can try. This is how to change the phone number you are dialing: For Redhat Linux servers: cd /etc/ppp/ [ENTER] Look for a file called pppd-args-chat.zol. That is the phone number file. vi pppd-args.chat.zol Make necessary changes and save the file. For Fedora Core 1: cd /etc/ppp/ [ENTER] vi phonenumber [ENTER] This command opens up the file "phonenumber" for editing. You should find a line that says something like: ABORT 'NO CARRIER' ABORT BUSY '' ATZ OK ATDT760400 CONNECT The number that comes after the letters ATDT is the current phone number (760400 in the example) Press I to get into insert mode. You should see -- INSERT -- at the bottom left hand corner of your screen. Move the cursor to the end of the phone number using the arrow keys, and use the BackSpace key to remove the number. Retype the new number. When you are done, press Esc to get out of insert mode. Type :x and press enter ([COLON] x [ENTER]) to save your changes. If you make a mistake and want to quit the phonenumber file without saving, press Esc, type :q! and press Enter ([COLON] q! [ENTER]). This should get you back to the command prompt and you can retype the vi phonenumber command to start afresh For Fedora Core 3 If your server runs a graphical interface, you may have a shortcut on the desktop called "Change Phone Number" which, after double-clicking, should automatically open the correct file for you to edit. If not, type these commands at the terminal: cd /etc [ENTER] vi wvdial.conf [ENTER] This command opens up the file "wvdial.conf" for editing. You should find a line that begins: Phone Number= The number that comes after the equals is the current phone number Press I to get into insert mode. You should see -- INSERT -- at the bottom left hand corner of your screen. Move the cursor to the end of the phone number using the arrow keys, and use the BackSpace key to remove the number. Retype the new number. When you are done, press Esc to get out of insert mode. Type :x and press enter ([COLON] x [ENTER]) to save your changes. If you make a mistake and want to quit the wvdial.conf file without saving, press Esc, type :q! and press Enter ([COLON] q! [ENTER]). This should get you back to the command prompt and you can retype the vi wvdial.conf command to start afresh. If you do not find the line mentioned above, follow the instructions detailed under Fedora Core 1.

BASIC TROUBLESHOOTING :

The Linux server will keep detailed logs of any errors that are generated during its' normal operation. All these logs are kept in the directory /var/log/ .If you are having any problems with the server, the first and best thing to do is to check the logs

cd /var/log/ [ENTER]

tail -f maillog [ENTER] for email problems.

tail -f messages [ENTER] for dialup problems

The logs for Internet browsing are kept in a different place, but the command to view them is the same, you just need to specify the correct path to the logs.

tail -f /usr/local/squid/var/logs/access.log

on older systems the command will be:

tail -f /usr/local/squid/logs/access.log

To stop the tail command from running and return to the command prompt type

Ctrl C ( that's control and the c key)

COMMON PROBLEMS WITH EMAIL INCLUDE:

User has entered in their username or password incorrectly. By tailing the maillog, you will be able to pick this up, and rectify the problem.

To restart different services on a linux server you can run the following commands:

service (name of service) restart ie:

service squid restart or

service network restart