Perfect Backup MX using Postfix

This is quite simple, and with a very simple setup, and does not require that much, since we do not need to send out e-mails from clients from this server, or use ASMTP. I find that MySQL is not needed here, but could be used. I will use normal flat files, since the number of domains to run a backup for is most likely a rather small number. 

This setup can be editet to run all times of different checks, antivirus etc.  Normally you would make sure that the setup is exactly the same on both the primary MTA, and the backup. It hardenens the systems, and should reduce spam, and unwanted traffic. Create public DNS entries. Remember to create an MX record with an lower priority than the primary mail server, or else this will not work! 

Example:example.com. 43200 IN MX 10 mail.example.com.
example.com. 43200 IN MX 20 backup.example.com.

After this these two records are created with A records pointing to different IPs (different servers).  Continue reading “Perfect Backup MX using Postfix” »

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Failed to open /var/mail/root : No such file or directory

If you’re receiving the following message on webmin- “Failed to open /var/mail/root : No such file or directory”.

Possible resolution is-

rumi@mordor:~$
rumi@mordor:~$ sudo touch /var/mail/rumi
rumi@mordor:~$ sudo chown thufir:mail /var/mail/rumi
rumi@mordor:~$ sudo chmod o-r /var/mail/rumi
rumi@mordor:~$ sudo chmod g+rw /var/mail/rumi
rumi@mordor:~$
rumi@mordor:~$ mail
No mail for thufir
thufir@mordor:~$

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Postfix using Gmail as a Mail Relay with Debian 7

Prerequisites

Before starting this tutorial, you should have:

  • Debian 7 installed
  • Your fully qualified domain name (FQDN)
  • All updates installed :
apt-get update

A valid username and password for the SMTP mail provider, such as Mandrill, or SendGrid
Make sure the libsasl2-modules package is installed and up to date:

apt-get install libsasl2-modules

Continue reading “Postfix using Gmail as a Mail Relay with Debian 7” »

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OpenDKIM Postfix SMTP Relay Server on Debian -7

Install OpenDKIM

Before starting the installation, a system update is recommended:

sudo apt-get update
sudo apt-get dist-upgrade

Install OpenDKIM and it’s dependencies:

sudo apt-get install opendkim opendkim-tools

Additional packages will be listed as dependencies, type yes and press Enter to continue.

Configure OpenDKIM

A couple of files must be created and edited in order to configure OpenDKIM.

Nano will be used as an editor because it’s installed by default on DigitalOcean droplets and it’s simple to operate:

navigate with the arrow keys
exit without saving changes: press CTRL + X and then N
exit and save changes: press CTRL + X and then Y, and finally press Enter
Important: replace every instance of example.com with your own domain in all commands and configuration files. Don’t forget to save your files after editing.

Let’s start with the main configuration file: Continue reading “OpenDKIM Postfix SMTP Relay Server on Debian -7” »

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DKIM installation on Debian

 

This is a quick and fairly painless way of setting up DKIM, on a postfix server. DomainKeys Identified Mail (DKIM) is a method for associating a domain name to an email message, thereby allowing a person, role, or organization to claim some responsibility for the message and helps verify that your mail is legitimate. This will help your email not get flagged a spam or fraud, especially if you are doing bulk emailing or important emails.

This tutorial is written for debian, so if using centos the paths to some files may be /etc/mail prefix or similar.

First, install dkim-filters

Debian based

apt-get install dkim-filter

Redhat Based

Enable EPEL

yum install dkim-milter Continue reading “DKIM installation on Debian” »

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Group-Office installation on Debian 6.x

I used the auto installation as guided by the group-office wiki. However, for conveniences, quoting the contents once again:

Easy installation on a dedicated Debian or Ubuntu server

This is the easiest way of installing Group-Office. With the debian packages everything is configured automatically and Group-Office updates will be installed automatically when you update your Debian or Ubuntu system.

Install Debian >= 5 or Ubuntu >=8.10

Note: All the commands here use "sudo". This is necessary on Ubuntu. If you are on Debian you can use the "su" command first and execute all the commands without "sudo".

Add the following line to /etc/apt/sources.list

deb http://repos.groupoffice.eu/ threeseven main

You can do that easily by executing the following command in the terminal:

echo -e "\n## Group-Office repository\ndeb http://repos.groupoffice.eu/ threeseven main" | sudo tee -a /etc/apt/sources.list

To authenticate the packages you need to import the public key by running the folowing commands: In ubuntu don't do this as root because you will have trouble with the gpg keyring permissions. On debian you can do this as root and omit the sudo command before the apt-key add command.

gpg –keyserver hkp://keyserver.ubuntu.com:11371 –recv-keys 01F1AE44

gpg –export –armor 01F1AE44 | sudo apt-key add –

Note: The keyservers are often very slow. If the keyserver doesn't respond you may try this one instead: hkp://pgp.mit.edu Continue reading “Group-Office installation on Debian 6.x” »

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Postfix Configuration on Centos 5.x

Let's install Postfix and Dovecot (Dovecot will be our POP3/IMAP server):

yum install cyrus-sasl cyrus-sasl-devel cyrus-sasl-gssapi cyrus-sasl-md5 cyrus-sasl-plain postfix dovecot

Next we configure SMTP-AUTH and TLS:

postconf -e 'smtpd_sasl_local_domain ='
postconf -e 'smtpd_sasl_auth_enable = yes'
postconf -e 'smtpd_sasl_security_options = noanonymous'
postconf -e 'broken_sasl_auth_clients = yes'
postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination'
postconf -e 'inet_interfaces = all'
postconf -e 'mynetworks = 127.0.0.0/8'

We must edit /usr/lib/sasl2/smtpd.conf so that Postfix allows PLAIN and LOGIN logins. On a 64Bit Centos 5.0 you must edit the file /usr/lib64/sasl2/smtpd.conf instead. It should look like this: Continue reading “Postfix Configuration on Centos 5.x” »

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