RedHatLinux9 -- set up the mail server -- Linux Enterprise Application-Linux server application information. The following is a detailed description.
1. Install Sendmail
If Red Hat Linux 9.0 is fully installed, the system has a built-in Sendmail 8.12.8-4 server. If you cannot determine whether sendmail has been installed, enter the following command in the terminal command window:
[Root @ ahpeng root] rpm-qa grep sendmail
If the result shows as a sendmail-8.12.8-4, it indicates that the sendmail server is installed. If the Sendmail server is not selected when Red Hat Linux 9.0 is installed, you can click the "Main Menu> system Settings> add or delete application" menu item in the graphic environment, in the open "software package management" dialog box, ensure that the "Mail Server" option is selected, and then click the "Update" button. Follow the on-screen prompts to insert the first installation disc to start installation.
Alternatively, you can insert 1st installation discs, locate the sendmail-8.12.8-4.i386.rpm installation package under the/RedHat/RPMS directory, and then run the following command in the terminal command window to start the installation process:
The following results should be displayed, indicating that the email server has been started successfully:
Start sendmail: [OK]
Start sm-client: [OK]
In addition to the preceding method, you can use the Sendmail command with parameters to control the running of the mail server. For example:
[Root @ ahpeng root] # sendmail-bd-q1h
The command parameters of Sendmail are described as follows:
-B: Specify Sendmail to run in the background and listen to requests on port 25.
-D: Specify Sendmail to run in Daemon mode (daemprocess ).
-Q: When Sendmail fails to send the email to the destination, it stores the email in the queue. This parameter specifies the time when the message is saved in the queue. In this example, 1 h indicates that the data is retained for 1 hour.
Run the following command in the terminal command window to restart the Sendmail service:
You can also run the following command in the terminal command window to check the running status of the Sendmail server:
[Root @ ahpeng root] #/etc/rc. d/init. d/sendmail status
The system should display:
Sendmail (pid 3251) is running...
3. configure Sendmail
The configuration of Sendmail is very complex. Its configuration file is sendmail. cf, which is located in the/etc/mail directory. Due to the profound Syntax of sendmail. cf, few users directly modify the file to configure the Sendmail server. We generally use the m4 macro processing program to generate the required sendmail. cf file. A template file is also required during the creation process. The system defaults to/etc/mail
The directory contains a sendmail. mc template file.
You can generate the sendmail. cf file based on the simple and intuitive sendmail. mc template without directly editing the sendmail. cf file. You can directly modify the sendmail. mc template to customize the sendmail. cf file. This section describes how to create a sendmail. cf file:
(1) back up the original sendmail. cf file
Run the following command in the terminal command window:
Cp/etc/mial/sendmail. cf/etc/mail/sendmail. cf. BAK
(2) generate the sendmail. cf file
Generate the sendmail. cf configuration file based on the sendmail. mc template file and export it to the/etc/mail/directory:
Obviously, it is convenient to use the m4 macro compilation tool to create the sendmail. cf file, which is not prone to errors and can avoid damages caused by some macros with security vulnerabilities or outdated macros. The general content of a sendmail. mc template is as follows:
Divert (-1) dnl
......
Include (/usr/share/sendmail-cf/m4/cf. m4) dnl
VERSIONID (setup for Red Hat Linux) dnl
OSTYPE (linux) dnl
......
Dnl #
Dnl define (SMART_HOST, smtp. your. provider)
Dnl #
Define (confDEF_USER_ID, 8:12) dnl
Define (confTRUSTED_USER, smmsp) dnl
Dnl define ('confauto_rebuild ') dnl
......
The syntax of the sendmail. mc template is described as follows:
Dnl: Used to annotate items, and the dnl command is also used to mark the end of a command.
Divert (-1): located at the top of the mc template file, to make the m4 program output more streamlined.
OSTYPE (OperationSystemType): defines the operating system type used. Obviously, linux should be used to replace OperationSystemType. Note that a back quotation mark and a positive quotation mark should be used to enclose the corresponding operating system type.
Define: defines some global settings. For Linux systems, after setting OSTYPE, you can define the following global parameters. If not, use the default value. Here are two simple examples: define (ALIAS_FILE,/etc/aliases)
Defines the Save path of the alias file. The default value is/etc/aliases.
Define (STATUS_FILE,/etc/mail/statistics)
Sendmail status information file.
4. open an email account for the new user
In Linux, it is relatively simple to open an email account for new users. You only need to add a new user in Linux. Click the "Main Menu> system Settings> users and groups" menu to open
In the Red Hat User Manager dialog box, click the Add User button and specify the user name and logon password in the create new user dialog box, as shown in figure 1.
Assume that we have added a user Peter (with the password peter) so that the user has an email address Peter@YourDomain.com (YourDomain.com here is replaced by your own domain name ).
You can also run the following command in the terminal command window to implement the above process:
[Root @ ahpeng root] # adduser peter-p peter
5. Set an alias for the email account
If you want to use multiple email addresses, do you need to create multiple email accounts? We can use the alias (alias) to solve this problem.
For example, peter wants to have the following three email addresses:
Peter@YourDomain.com,
Dearpeter @ YourDomain.com and truepeter @ YourDomain.com.
You can perform the following steps to set an alias:
Add an account peter. Then open/etc/aliases in a text editor such as vi or Kate and add two lines to it:
Dearpeter: peter
Truepeter: peter
Save/etc/aliases and exit.
However, Sendmail cannot accept the new alias. We must run the newaliases command in the terminal command window to request Sendmail to re-read the/etc/aliases file. If everything is correct, you can see a Response Message similar to the following:
[Root @ ahpeng root] # newaliases
/Etc/aliases: 63 aliases, longest 10 bytes, 625 bytes total
In this way, the mail sent to peter can use three mail addresses, while peter only needs to use an email account peter@YourDomain.com to receive all the emails sent to the above three addresses.
6. Specify the mailbox Capacity Limit
When a mail server provides mail services for many people, an unlimited number of emails can easily fill the server's hard disk, causing a hard disk burden. If you do not want to provide unlimited temporary storage space for emails, you can use "mail quota" to provide users with a limited temporary storage space.
In fact, it is achieved by using the disk quota function. The temporary storage space for email is in the/var/spool/mail directory. You only need to set the maximum space that each user can use in this directory through the disk quota.
7. Support for POP and IMAP Functions
So far, we can use Outlook Express to send emails, or log on to the server to use mail and pine commands to receive and manage emails. However, you cannot use clients such as Outlook Express to download emails from the server. This is because Sendmail does not have the POP3 (IMAP) function, so we must install it on our own.
(1) install POP and IMAP servers
When installing Red Hat Linux 9.0, you can install the POP and IMAP servers. You can run the following command in the terminal command window to verify the installation:
[Root @ ahpeng root] # rpm-qa imap
Imap-2001a-18
If no installation is available, you can put 2nd installation discs into the optical drive, and then run the following command in the terminal command window to start installation:
Since Red Hat Linux 9.0 has packaged POP and IMAP into a separate suite, installing the imap-2001a-18.i386.rpm will install both servers at the same time
(2) Start POP and IMAP services
To successfully start the POP and IMAP servers, you must first determine that these services exist in the/etc/services file and ensure that the following services are not preceded by # annotations (if any, annotations must be removed ).
Imap 143/tcp imap2 # Interim Mail Access Proto v2
Imap 143/udp imap2
Pop2 109/tcp pop-2 postoffice # POP version 2
Pop2 109/udp pop-2
Pop3 110/tcp pop-3 # POP version 3
Pop3 110/udp pop-3
After modifying the/etc/services file, you need to customize the corresponding service configuration file:
To start the POP3 service, you must modify the/etc/xinetd. d/ipop3 file, change "disable = yes" to "disable = no", and save the file. Finally, you must restart the xinetd program to read the new configuration file so that the configuration content takes effect:
To start the IMAP service, you must modify the/etc/xinetd. d/imap file, change "disable = yes" to "disable = no", and save the file. Finally, you must restart the xinetd program to read the new configuration file so that the configuration content takes effect:
After setting up, you can set up an email account in Outlook Express, and then you can directly use the Sendmail server to send and receive emails. Because the mail server is on the local LAN, the speed is very fast.
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