File Management (GUI)

Managing files in GUI mode is a simple as launching the File Browser.

1. Click Applications, select System Tools then click File Browser. This will launch the File Browser window.

2. From the File Browser tool you can now perform your desired file operation.

File Management (Console)

Below are the console commands to manage files. This is just an overview of the commands available, to get more information, type in man command to get the manual for the specified command.

Common Operations

• cp -a source dest
  copy the specified file or directory
• rm -rf name
  delete the specified file or directory and all of its contents
• mv old new
  move a file or directory to a new location. Also used to rename a file or directory
• ln -s source linkname
  create a symbolic link to the specified file or directory

Directory Operations

• cd
  change to the home directory
• cd path
  change to the specified directory
• pwd
  print working directory
• ls
  list directory
• mkdir name
  create the specified directory
• rmdir name
  delete the specified directory. Directory should be empty

File Operations

• chown owner file
  change the file owner to the specified user
• chmod permissions files
  change the file permissions
• cat name
  shows the file content
• more name
  shows the file content a few screens at a time
• less name
  shows the file content similar to how vi displays a file
• vi name
  edit the specified file. Learn how to use the vi editor
• head name
  shows the first few lines of a file
• tail name
  shows the last few lines of a file

Configure Network Device (GUI)

This section describes how to configure the network device using GUI tools.

1. Click System, select Administration then click Network. This will launch the Network Configuration window.

2. Select the network device you want to modify and click Edit.

3. In the Ethernet Device window, apply your changes and click OK.

4. Click the DNS tab and apply your DNS settings.

5. To save your changes, click the File and click Save.

6. To effect your changes, click the Devices tab. Next, select the device and click Deactivate then click Activate to reactivate the device.

7. Update your /etc/hosts file.

Although the Network Configuration tool has a feature to update the /etc/hosts file, it is more reliable to edit it directly instead.

Configure Network Device (TUI)

This section describes how to configure the network device using text user interface (TUI) tools.

1. Launch the Network Configuration TUI tool using the command below. Then apply the necessary changes to your network device.

system-config-network-tui

2. To effect your changes, restart the network service using the command below.

service network restart

3. Update your /etc/hosts file.

Configure Hosts

1. Click Applications, select System Tools then click File Browser. This will launch the File Browser window.

2. In the Location field, type in /etc and press Enter. If you don’t see the Location field, click the notepad button to toggle to text-based location bar.

3. Locate and double click on the file hosts to open it for editing. Update the content similar to the lines below.

127.0.0.1       localhost.localdomain localhost
::1             localhost6.localdomain6 localhost6
192.168.0.4     mail.acme.local mail

Replace the last line with your own IP address, fully qualified domain name and host name.

Test the Host Name Lookup

1. Click Applications, select Accessories, and click Terminal. This will launch the Terminal window.

2. In the terminal window, type in the command below.

ping localhost

You should see localhost.localdomain and 127.0.0.1

3. Next, type in the command below.

ping mail

Replace mail with your own hostname. You should see your fully qualified domain name and ip address.

1. Install the requirements using the command below.

yum install mysql-server php-pear-DB

2. Start the mysqld service. Learn how to start and stop services here.

3. Launch the MySQL command line tool using the command below.

mysql -u root -p

The default root password of MySQL is a blank password. Next, create a new MySQL database for SquirrelMail using the commands below.

mysql> CREATE DATABASE squirrelmail;
mysql> CREATE USER squirrelmail@localhost IDENTIFIED BY 'your_password';
mysql> GRANT ALL PRIVILEGES ON squirrelmail.* TO squirrelmail;
mysql> USE squirrelmail;
mysql> CREATE TABLE address (
  owner varchar(128) DEFAULT '' NOT NULL,
  nickname varchar(16) DEFAULT '' NOT NULL,
  firstname varchar(128) DEFAULT '' NOT NULL,
  lastname varchar(128) DEFAULT '' NOT NULL,
  email varchar(128) DEFAULT '' NOT NULL,
  label varchar(255),
  PRIMARY KEY (owner,nickname),
  KEY firstname (firstname,lastname)
);
mysql> CREATE TABLE global_abook (
  owner varchar(128) DEFAULT '' NOT NULL,
  nickname varchar(16) DEFAULT '' NOT NULL,
  firstname varchar(128) DEFAULT '' NOT NULL,
  lastname varchar(128) DEFAULT '' NOT NULL,
  email varchar(128) DEFAULT '' NOT NULL,
  label varchar(255),
  PRIMARY KEY (owner,nickname),
  KEY firstname (firstname,lastname)
);

4. Configure SquirrelMail the command below.

/usr/share/squirrelmail/config/conf.pl

Select menu 9, Database and update the values of the following.

• DSN for Address Book : mysql://squirrelmail:password@localhost/squirrelmail
• DSN for Global Address Book : mysql://squirrelmail:password@localhost/squirrelmail
• Allow writing into Global Address Book : true
• Allow listing of Global Address Book : true

Then save your changes. Your address book should now be stored in MySQL.

Create the Virtual Mail User Account

1. Create a new user, we will call it vmail. Change the Login Shell to /sbin/nologin, this user account should not be used for logging in. Learn how to use the User Manager application here.

2. Take note of the User ID and Home Directory of vmail.

3. Click the Groups tab and now note down the Group ID of vmail. We’ll be needing all of them later.

Configure Postfix for Virtual User Accounts

1. Edit the postfix configuration file /etc/postfix/main.cf and edit the line below

mydestination = $myhostname, localhost.$mydomain, localhost

and add the lines below

virtual_mailbox_domains = $mydomain
virtual_mailbox_base = /home/vmail/
virtual_mailbox_maps = hash:/etc/postfix/vmailbox
virtual_uid_maps = static:501
virtual_gid_maps = static:501

virtual_mailbox_base, virtual_uid_maps and virtual_gid_maps should contain the home directory, user id and group id of vmail respectively.

2. Create the file /etc/postfix/vmailbox containing the mapping from an email address to a mailbox path relative to virtual_mailbox_base. See the example below.

johndoe@acme.local johndoe/Maildir/
janedoe@acme.local janedoe/Maildir/

3. Type in the command below to generate the static db that will be used for the lookup.

postmap /etc/postfix/vmailbox

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

5. Try sending an email. See Test Postfix using Telnet. New mails should now be stored under the path specified in virtual_mailbox_base.

Configure Dovecot Virtual User Accounts

1. Edit the file /etc/dovecot.conf and change the value of the following keys below

passdb static {
  args = /etc/dovecot-passdb
}

userdb static {
  args = uid=501 gid=501 home=/home/vmail/%u
}

uid, gid and home should contain the user id, group id and home directory respectively of the vmail user account.

Make sure comment out all the other passdb and userdb sections to avoid any conflicts.

2. Create the file /etc/dovecot-passdb containing the password of a user name. See the example below.

johndoe:{PLAIN}secret
janedoe:{HMAC-MD5}dd59f669267e9bb13d42a1ba57c972c5b13a4b2ae457c9ada803dc7d8bae4ab

You can generate a hash password using the dovecotpw command.

3. Restart the dovecot service. Learn how to start and stop services here.

4. Test Dovecot using Telnet. You should be able to read the recently sent mail which was stored in a new location.

Restrict Sender

This section describes how to allow/reject a specific sender or a specific domain.

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

smtpd_sender_restrictions = 
  check_sender_access hash:/etc/postfix/sender_access

2. Create the file /etc/postfix/sender_access and review the example below.

janedoe@acme.local  REJECT
bugsbunny@acme.com  OK
acme.com            REJECT

3. Type in the command below in a terminal window to create a hash file.

postmap /etc/postfix/sender_access

4. Restart the Postfix or MailScanner service. Learn how to restart services.

Restrict Recipient

This section describes how to allow/reject a specific recipient or a specific domain.

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

smtpd_recipient_restrictions = 
  check_recipient_access hash:/etc/postfix/recipient_access,
  reject_unauth_destinations

2. Create the file /etc/postfix/recipient_access and review the example below.

janedoe@acme.local  REJECT
bugsbunny@acme.com  OK
acme.com            REJECT

3. Type in the command below in a terminal window to create a hash file.

postmap /etc/postfix/recipient_access

4. Restart the Postfix or MailScanner service. Learn how to restart services.

Restrict Sender and Recipient

This section describes how to restrict both the sender and recipient. Example usage of this is when you have a private domain which should not be allowed to send to the internet.

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

smtpd_recipient_restrictions = 
  check_sender_access hash:/etc/postfix/sender_access,
  reject_unauth_destinations

smtpd_restriction_classes = local_only
local_only = check_recipient_access hash:/etc/postfix/local_domains, 
  reject

2. Create the file /etc/postfix/sender_access and review the example below.

acme.local  local_only

3. Create the file /etc/postfix/local_domains and review the example below.

acme.local  OK

4. Type in the command belows in a terminal window to create the hash files.

postmap /etc/postfix/sender_access
postmap /etc/postfix/local_domains

5. Restart the Postfix or MailScanner service. Learn how to restart services.

1. Edit the file /etc/MailScanner/reports/en/inline.sig.txt and /etc/MailScanner/reports/en/inline.sig.html and replace it with your own message.

2. Edit the file /etc/MailScanner/MailScanner.conf and update the line below.

Sign Clean Messages = /etc/MailScanner/rules/signing.rules

3. Create the file /etc/MailScanner/rules/signing.rules and add the lines below.

From:      *@acme.local  yes
FromOrTo:  default       no

Replace acme.local with your own domain name.

4. Restart the MailScanner service. Learn how to restart services.

5. You should now see your disclaimer message on outbound emails.

DMZ Mail Server

The DMZ mail server forwards the inbound mail to the internal mail server and delivers the outbound mail.

1. Edit /etc/postfix/main.cf and update the lines below.

mydestination = 
local_recipient_maps = 
local_transport = error:local mail delivery is disabled

mynetworks = 127.0.0.0/8 192.168.1.3
relay_domains = example.com
transport_maps = hash:/etc/postfix/transport
smtpd_recipient_restrictions = permit_mynetworks
    reject_unauth_destination

The first three lines above disables local delivery. Replace 192.168.1.3 with the IP address of your internal mail server.

2. Edit the file /etc/postfix/transport and add the line below.

example.com :[192.168.1.3]

Replace 192.168.1.3 with the hostname or IP address of your internal mail server.

3. Type the line command below to create a transport database file.

postmap /etc/postfix/transport

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

5. You should now be able to send mails to your DMZ mail server and those mails will be automatically relayed to your internal mail server. See Test Postfix using Telnet.

Internal Mail Server

The internal mail server holds the mailbox and forward all outbound mail to the DMZ mail server for delivery. Make sure you have working Postfix mail server.

1. Edit /etc/postfix/main.cf and update the lines below.

transport_maps = hash:/etc/postfix/transport

2. Edit the file /etc/postfix/transport and add the lines below.

example.com    :
.example.com   :
*              smtp:[192.168.3.2]

Replace 192.168.3.2 with the hostname or IP address of your DMZ mail server.

3. Type the line command below to create a transport database file.

postmap /etc/postfix/transport

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

5. Your outbound mail should now be sent the DMZ mail server. See Test Postfix using Telnet.

SMTP Gateway Notes

It is easy to setup an SMTP gateway mail server but you also need to consider the items below.

• Add Antivirus and Antispam Filtering. Since the DMZ mail server is exposed on the internet, make sure it has anti-virus and anti-spam filtering.

• Verify Recipient. If possible, you also need to apply the same recipient verification method you used in your internal mail server. This will allow your DMZ mail server to reject all invalid recipient address instead of having the internal mail server bounce the relayed emails with invalid recipients. Use the relay_recipient_maps setting in /etc/postfix/main.cf to specify the valid recipients.

• Use IP Address. By specifying the hostname or IP address in the transport file, the DNS MX lookup can be eliminated. Specifying the IP address will be even better since this will eliminate the need for any DNS lookup.

• Flush Mail Queue. You can force Postfix to immediately send all the mail in its queue by typing in the command below.

  postfix flush