Month: May 2010

Relay Exim mail to google mail in Debian Linux

Posted on by admin

Sometimes its necessary to relay your mail through a third party provider. If your server environment has a dedicated sendmail server (most do), then this scenario is applicable to you. It is ideal to centralize your outgoing mail to one server so that changes, policies and configuration is located in a single place.

In this scenario, outgoing mail is relayed to google’s domain mail in an Exim mail environment. These steps are fairly straightforward and will hopefully help you to utilize google’s free mail service to send your mail.

Note that google has queuing and mass mail restrictions so if you plan on sending alot of mail this way, you will just get blocked.

    Step 1

Run dpkg-reconfigure exim4-config

1. Choose mail sent by smarthost; received via SMTP or fetchmail

2. Type System Mail Name: e.g. company.com

3. Type IP Adresses to listen on for incoming SMTP connections: 127.0.0.1

4. Leave Other destinations for which mail is accepted blank

5. Leave Machines to relay mail for: blank

6. Type Machine handling outgoing mail for this host (smarthost): smtp.gmail.com::587

7. Choose NO, don’t hide local mail name in outgoing mail.

8. Chose NO, don’t keep number of DNS-queries minimal (Dial-on-Demand).

9. Choose mbox

10. Choose NO, split configuration into small files

11. Mail for postmaster. Leaving blank will not cause any problems though it is not recommended

    Step 2

1. Open the file /etc/exim4/exim4.conf.template
2. Find the line .ifdef DCconfig_smarthost DCconfig_satellite and add the following in that section

 send_via_gmail:
 driver = manualroute
 domains = ! +local_domains
 transport = gmail_smtp
 route_list = * smtp.gmail.com

If you have any other smarthost defined with “domains = ! +local_domains” remove that smarthost.

3. Find the “begin authenticators”. In that section add the following

 gmail_login:
 driver = plaintext
 public_name = LOGIN
 client_send = : yourname@gmail.com : YourGmailPassword

Make sure you have no other authenticators with the same public_name (LOGIN). Comment them out if needed (Thanks Jakub for reminding me)

4. Find the comment “transport/30_exim4-config_remote_smtp_smarthost”. In that section add

 gmail_smtp:
 driver = smtp
 port = 587
 hosts_require_auth = $host_address
 hosts_require_tls = $host_address
    Step 3

1. Run update-exim4.conf

2. Do /etc/init.d/exim4 restart

That should be it. You can test by using the command line mail client.

Test :

 echo "test" | mail -s "subject" test@email-to-send-to.com

Integrate your custom IPTables script with Linux

Posted on by admin

How do I integrate my custom iptables script with Red Hat Enterprise Linux?

A custom iptables script is sometimes necessary to work around the limitations of the Red Hat Enterprise Linux firewall configuration tool. The procedure is as follows:

1. Make sure that the default iptables initialization script is not running:

service iptables stop

2. Execute the custom iptables script:

sh [custom iptables script]

3. Save the newly created iptables rules:

service iptables save

4. Restart the iptables service:

service iptables restart

5. Verify that the custom iptables ruleset have taken effect:

service iptables status

6. Enable automatic start up of the iptables service on boot up:

chkconfig iptables on

The custom iptables script should now be integrated into the operating system.

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