Postfix Quota for redhat mail user

Postfix does not support mailbox quota. But thanks to Anderson Nadal’s Postfix Virtual Delivery Agent (VDA) patches, it can. To use the Postfix VDA requires two things, first Postfix must be built with the VDA patches and second, virtual user accounts must be used. You can get the Postfix RPM with VDA patches here.

Here are some configuration you can use for your virtual accounts.

• Text File
• Active Directory/LDAP
• MySQL

Configure Postfix VDA

1. Edit the postfix configuration file /etc/postfix/main.cf and add the lines below

virtual_mailbox_limit_override = yes
virtual_overquota_bounce = yes
virtual_mailbox_limit_maps = hash:/etc/postfix/vquota

2. Create the file /etc/postfix/vquota containing the mapping from an email address to the maximum mailbox quota in bytes. If you wish to be exact, 1KB equals 1024 bytes while 1MB equals 1024KB or 1048576 bytes.

johndoe@acme.local 10485760
janedoe@acme.local 2097152

John Doe got a 10MB quota while Jane Doe got 2MB.
After creating this file, execute postmap /etc/postfix/vquota. This will generate /etc/postfix/vquota.db, the actual file that will be used for the lookup.
If you use Active Directory as your Postfix virtual user accounts source, you can use the maxStorage attribute instead to store the quota. Just copy your ldap-users.cf configuration and save it as ldap-quota.cf. Next change samaccountname to maxstorage in the result_attribute line and remove the result_format line. In your main.cf, use ldap:/etc/postfix/ldap-quota.cf as your virtual_mailbox_limit_maps. In Windows, you can use ADSI Edit to access and modify the value of maxStorage.

3. Restart the Postfix or MailScanner service if you have installed MailScanner. Learn how to start and stop services here.

4. Test Postfix using Telnet. Try using a very small quota limit so you can test the quota feature.

Postfix Aliases and Mailing List for redhat 6

You can create a text file in Postfix containing an alias email and several destination emails. There are two ways to implement aliasing and mailing list in Postfix depending on how it is configured.

For System Accounts

Your Postfix is configured to use system accounts if your configuration file has something like

mydestination = $mydomain

or sending to a non-existent account gives the error message

Recipient address rejected: User unknown in local recipient table

1. Edit the file /etc/aliases. The file has the form

alias: address1,address2

If address has the same domain as yours, you can leave it out. Thus you can use the /etc/aliases file to alias an email address or to build a mailing list.

2. Type in the command newaliases in a terminal window. This will rebuild the aliases database file.

For Virtual Accounts

Your Postfix is configured to use virtual accounts if your configuration file has something like

virtual_mailbox_domains = $mydomain

or sending to a non-existent account gives the error message

Recipient address rejected: User unknown in virtual mailbox table

1. Edit the file /etc/aliases. The file has the form

alias address1,address2

2. Generate the database file for valias using the command

postmap /etc/postfix/valias

3. Test your database file using the command

postmap -q group@acme.local /etc/postfix/valias

Replace group@acme.local with a valid alias entry. You should see the destination emails.

4. Edit the file /etc/postfix/main.cf and add the line below to your virtual settings section

virtual_alias_maps = hash:/etc/postfix/valias

If you are using virtual accounts, instead of maintaining a text file containing the aliases and mailing list, it would be better if you can work with your virtual accounts source. See the links below for examples

• Active Directory
• MySQL

To Test Postfix

1. Restart the Postfix service. But if you installed MailScanner, then restart MailScanner instead. This will immediately reload the aliases database file instead of after a few minutes.

2. You should now be able to send email to addresses found in your aliases file. See Test Postfix using Telnet and try using the alias email addresses

Firewall Configuration Howto for RHEL/CentOS 6 for mail server configuration

Red Hat Enterprise Linux 6 and its derivative CentOS 6 includes a graphical tool called Firewall Configuration for configuring the firewall options. This article describes how to use the Firewall Configuration tool to open up the ports necessary for providing an email server.

Firewall Configuration (GUI)

This section describes how to use the Firewall Configuration tool to configure the firewall.

1. Click System, select Administration and click Firewall. This will launch the Firewall Configuration window.

2. Click Close in the Firewall Configuration Startup window.

3. Type in the root password and click Authenticate.

If the Firewall Configuration Startup window does not disappear after clicking Close, click the window behind it to bring the Authenticate window into the foreground.

4. In the service list, check Mail (SMTP) and WWW (HTTP).

5. Click Other Ports and click Add.

6. Select 110 tcp pop3 and click Ok. Do the same for 143 tcp imap.

7. Finally, click Apply to save your changes.

Firewall Configuration (TUI)

This section describes how to use the Firewall Configuration text user interface (TUI) tool to configure the firewall.

1. Launch the Firewall Configuration tool using the command below.

system-config-firewall-tui

2. In Firewall Configuration screen, press the Customize button.

3. In the service list, check Mail (SMTP) and WWW (HTTP). Press Forward when you are done.

4. Press Add to add a custom port.

5. Type in 110 to the field Port and tcp to the field Protocol. Press OK when you are done. Do the same for 143:tcp.

6. After adding the two ports press Close.

7. Finally, press OK and press Yes to confirm overriding of firewall configuration.

 

You can see the list of service and port numbers using the command below.

getent services