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Backing Up a Gmail Account With Fetchmail on FreeBSD

October 17, 2011

Gmail is awesome. But I do not want Gmail to be the only location where all my important emails are stored. For this reason I use fetchmail to automatically archive any emails sent to my Gmail account on my own FreeBSD server. This guide describes how I currently have this set up.

Ingredients

Installing Required Packages

If you haven't already, install the fetchmail port with the following commands.

$ cd /usr/ports/mail/fetchmail
$ make install clean

We also need to install the ca_root_nss port. This port contains all root certificates from certificate authorities included in Mozilla applications (i.e. Firefox and Thunderbird).

$ cd /usr/ports/security/ca_root_nss
$ make install clean

Configuring

First, make sure that you have POP access to your Gmail account enabled. This can be done from the Gmail settings page, under the tab ‘Forwarding and POP/IMAP’.

Next, calculate the MD5 fingerprint for the pop.gmail.com certificate. Whenever Google makes a change to the certificate this fingerprint has to be recalculated and updated in the fetchmail configuration.

$ echo -n | 
  openssl s_client -connect pop.gmail.com:995 | 
  sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | 
  openssl x509 -noout -fingerprint -md5 | 
  cut -d '=' -f 2

Customize the following snippet and place it in ~/.fetchmailrc.

poll pop.gmail.com protocol pop3 with interval 3:
  user "<your Gmail address>" pass "<your Gmail password>"
  options keep ssl sslfingerprint "<actual MD5 fingerprint>"
  mda "/usr/bin/procmail -d %T"

Testing

That should be all, now we can test our configuration.

$ fetchmail -d0 -v pop.gmail.com

If everything is set up correctly then the output should look something like this:

fetchmail: 6.3.20 querying pop.gmail.com (protocol POP3) at Sun Oct 16 19:25:01 2011: poll started
Trying to connect to 209.85.227.109/995...connected.
fetchmail: Server certificate:
...
fetchmail: POP3> QUIT
fetchmail: POP3< +OK Farewell.
fetchmail: 6.3.20 querying pop.gmail.com (protocol POP3) at Sun Oct 16 19:25:02 2011: poll completed