Even though this system makes it easy to set up an email server, running your own email system is still not easy and this is mainly due to the huge amount of collatoral damage caused by spammers over a long period of time, which in turn is due to the inherent insecurity of email protocols which enabled spam to become a big problem. Email is still very popular though and most internet services require that you have an email address in order to register.

In using an email address hosted on your own system you will quite likely find that it is blocked and bounced by other popular email systems. Such blocking is almost never based upon any evidence that your system is actually producing spam and usually it's just because your IP address happens to be within a certain range. Rather arrogantly many of the anti-spam rule sets assume that if an email is sent from an IP address range which is "residential" (i.e. not a company or other organisation) then it must therefore be spam.

So if you want to use your own email address hosted on your own system you do need to be prepared to encounter some difficulties and annoyances. Sadly, often these annoyances will be unsolvable and are not a matter of using different software or configuring things differently.

Port 465 is used for SMTP and this is supposedly deprecated for secure email. However, using TLS from the start of the communications seems far more secure than starting off with insecure communications and then trying to upgrade it with a command to begin TLS, as happens with STARTTLS. There are possible attacks against STARTTLS in which the command to begin secure communications is removed or overwritten which could then result in email being transferred in plain text over the internet and be readable by third parties.

From https://motherboard.vice.com/read/email-encryption-is-broken:

The researchers also uncovered mass scale attacks of STARTTLS sessions being stripped of their encryption. That attack itself isn't new: internet service providers sometimes do it to monitor users; organizations may use it to keep an eye on employees; or it may come from a malicious actor

A way to avoid these pitfalls altogether is to use onion addresses (see the section below) or I2P addresses for email. These are not so convenient because they use long random strings which aren't memorable as addresses, but they do give a strong assurance that whoever recieves the message is the intended recipient and that emails can't be read passively during their transport across the internet.

If you didn't use existing GPG keys during the Freedombone installation then you'll need to add a password to your newly generated private key. This is highly recommended. Go through the following sequence of commands to ssh into the Freedombone and then change your GPG password.

ssh username@domainname -p 2222
gpg --edit-key username@domain
passwd
save
quit
exit

Having a password on your GPG key will prevent someone from reading your email even if your server gets lost or stolen or if someone else has physical access to it. Make the password something long and unlikely to be guessable or vulnerable to a brute force dictionary attack.

If you havn't already then you should publish your GPG public key so that others can find it.

ssh username@domainname -p 2222
gpg --send-keys username@domainname
exit

Mutt is a terminal based email client which comes already installed onto the Freedombone. To access it you'll need to access it via ssh with:

ssh username@domainname -p 2222

If you're using Windows there is an ssh client called putty, on Linux just open a terminal and enter the above command with your username and domain name. On Android you can use the ConnectBot app with the hostname username@domain:2222

Once you have logged in via ssh then just type mutt. Like most terminal programs mutt is quite easy once you've learned the main keys.

Some useful keys to know are:

To use the address book system open an email by pressing the enter key on it and then to add the sender to the address list press the A key. It will ask you for an alias which may be used the next time you want to send a mail. Alternatively you may just edit the ~/.mutt-alias file directly to add email addresses.

One of the most common things which you might wish to do is to send an email. To do this first press m to create a new message. Enter the address to send to and the subject, then after a few seconds the Emacs editor will appear with a blank document. Type your email then press CTRL-x CTRL-s to save it and CTRL-x CTRL-c to exit. You will then see a summary of the email to be sent out. Press y to send it and then enter your GPG key passphrase (the one you gave when creating a PGP/GPG key). The purpose of that is to add a signature which is a strong proof that the email was written by you and not by someone else.

When reading emails you will initially need to enter your GPG password. It will be retained in RAM for a while afterwards.

There is one irksome thing about email within mutt, and that's if you get sent a confirmation with a very long URL. It's usually not possible to view URLs which span over multiple lines, and trying to copy/paste them is annoying. A solution is to use CTRL-u then select the url and press Enter. You can then navigate to it via the lynx browser.

Another common way in which you may want to access email is via Thunderbird (also known as Icedove on Debian). This may be especially useful if you're trying to convert former Windows users who may previously have been using some version of Outlook.

The following instructions should be carried out on the client machines (laptop, etc), not on the BBB itself.

Mobile devices have a reputation for being quite insecure, so it's recommended that you don't store emails or GPG keys on your phone. Instead install Mailpile and access your email via the webmail interface.

To subscribe to a mailing list log in as your user (i.e. not the root user).

ssh username@domainname -p 2222

Select Administrator controls then Email filtering rules then Add a user to a mailing list. If you want to do it purely from the commandline then see the manpage for freedombone-addlist.

Similar to adding mailing list folders you can also add specified email addresses into a group/folder.

ssh username@domainname -p 2222

Select Administrator controls then Email filtering rules then Add email rule. To do the same from the commandline see the manpage for freedombone-addemail.

It is possible to ignore incoming emails if they are from a particular email address or if the subject line contains particular text.

ssh username@domainname -p 2222

Select Administrator controls then Email filtering rules then Block/Unblock and email address or Block/Unblock email with subject line. Also see the manpage for freedombone-ignore.

By default this system comes with the ability to send and receive emails using onion addresses as the domain name. On the user control panel if you select Show your email address then you should find one ending with dot onion. You will also see a QR code for that address, which provides a simple way to transfer it to a mobile phone if necessary.

If you want to give your onion email address to someone else securely then you can use the QR code to transfer it to a phone and copy and paste the address into an encrypted chat app, such as Conversations. Of course they will probably also need to be running Freedombone or some system capable of handling onion email addresses.

When sending email from an onion address it's not strictly necessary to use GPG/PGP. Tor handles the transport security by itself. You can still use it though if you prefer to have an extra layer of message security. You can also still use onion email addresses even if your ISP blocks the typical email ports (25 and 465).

If you don't make your onion email address public then it should be fairly resisent to spam, since spammers won't be able to randomly guess onion addresses (there are far too many), whereas it's a lot easier for them to do that with conventional domain names.

For the most paranoid use cases it is also possible to use I2P as an email transport mechanism. This will of course require the people you're communicating with to have a similar setup in place. For details see the bdsmail app. An advantage of this is that it's very unlikely that your email will get blocked. The disadvantage is that few others will be capable of receiving email this way, and it's only really usable via the Mutt email client.