LincolnBlogs

What is a personal IMAP mail server and why would you want one? Well, such a server is, like it sounds, your very own mail server that you can access via IMAP. You might want such a thing because, like me, you have a lot of different email accounts in different places and you want to collect them all into one central and easy to manage location. I also like having more direct control over my access to my email. For example, if your email account at somewhere.com stops working because their server is down and you need to reference an email stored there, you are out of luck, unless you store your somewhere.com email on your own email server where you can still access it even though their server is inaccessible.

Since I am doing some personal server upgrades and migration, I thought it would be great to share just how to get this kind of server up and running with the most minimal hassle.

For starters, my new mail server is going to be a 32 bit server install of CentOS 5.3. This OS is not at all difficult to install at all and it’s enterprise ready, so it’s plenty reliable.

When you have a machine ready with CentOS running on it, you will need to install Dovecot to handle your IMAP mail access. This is just an yum install away:

yum -y install dovecot

You will need to configure Dovecot after the install. Edit the /etc/dovecot.conf file and make sure the following is set and uncommented:

protocols = imap imaps
mail_location = maildir:~/Maildir

CentOS uses a sendmail/procmail mail combo by default, so in order to make sure your server and IMAP are both using Maildir (so your email gets delivered to you locally) you’ll need to create a file called /etc/procmailrc and in it put:

DEFAULT=$HOME/Maildir/

And then restart your mail service (just to make sure):

service sendmail restart

Once that is set, you will need to turn on Dovecot!

chkconfig dovecot on
service dovecot start

At this point, you should be able to (firewall issues not withstanding) connect to your new mail server via IMAP and see that you have no mail. I am assuming that you have set up mail clients before, the only difference now is you will point to “YourNewMailServerName” and set it up for IMAP mail and use your account name and password from “YourNewMailServerName”.

For example, I created a new server called “Pukwudgie.linc.lan” and created an account on it called linc and made a supersecret password. When I set up my mail client to test the mailserver setup, I set it up to point to Pukwudgie.linc.lan using my username of linc and my password of supersecret via the IMAP protocol. I was able to log directly into my new mail account, which was completely empty.

At some point, you will want to SEND some mail from this account. Since this personal IMAP server is just a place to HOLD your emails, you will need to configure your email client to use your ISP’s smtp address to send through. Follow their instructions for doing this. Most ISP’s do not allow you to use any smtp server other than their own these days.

Now for the fun part. You wan to collect your mail from other places and store it here. This is accomplished through the use of fetchmail. You will need to place a “~/.fetchmailrc” file in your home directory. Please refer to the fetchmailrc man page for full details, but in essence mine looks a lot like this:

poll lincisgreat.org user "linc" there with password "itsasecret"

And you can have as many of those lines in that file as you have email accounts. After creating the rc file, you can run fetchmail to get your mail and have it delivered locally on your new server, where you can access it via IMAP. There are several methods of running fetchmail. You can run it by itself and watch the output as it goes each time, you can run it in daemon mode by starting it with the -d command line switch and specifying a time interval:

fetchmail -d 60

Will check for and grab your email every 60 seconds. Or you could put fetchmail in your crontab and have cron manage getting your mail like so:

*/5 * * * * /usr/bin/fetchmail &> /dev/null

Which would check your email every 5 minutes.