Thunderbird as MUA for i2p mail


Once I had I2P properly running, I got me a mail account from hq.postman.i2p. Accounts can send and receive mail from the normal internet. Postman’s I2P-based mail system can be accessed either via I2P’s built-in mail client (susimail) or using any mail client that supports smtp and pop3. But not all clients are suitable for that.

Security Basics guide by Postman H

  • Get a dedicated mail client for use with I2p mail only.
  • Install and configure the system in a way that all configuration data and mail folders are stored on a safe and possibly encrypted partition.
  • Check the configuration. A few mail clients allow the specification of a dedicated HELO host-name to be used. Other MUA allow the creation of certain header lines to be prohibited (like Message-ID and Received).
  • Compose a mail and store it in the outgoing folder or send it to one of your internet mail addresses. Look at the mail source. Check for any lines relevant to anonymity. This is the way the mail will later be sent to the postman system.
  • Install and configure a PGP compatible software like OpenPGP, GNUPG or enigmail. Public keys of mail users are available from the postman.i2p public address book.


Not all MUAs work the same when it comes to composing and sending a mailmessage, thus exposing more or less information to the SMTP server. While smtp.postman.i2p will sanitize ALL security relevant headers it’s still preferred to not create sensitive data in the first place. And this is where different MUAs work differently.

Sylpheed Claw does well, and so does Thunderbird.

Program: Sylpheed Claws
Platforms: Linux / Windows
Observations: By default exposes version number and platform of the operating system (i686-linux-gnu/win32) and creates a message ID containing a local timestamp and the sender’s mail address. You can and should configure sylpheed to change its behaviour to not sending a message id header at all. By default sylpheed uses the locally configured hostname as HELO string. This setting can be changed too and you should do so when using it with i2p mail. As a bonus sylpheed can be configured to not create a Date headerline which is helpful for not exposing your local timezone.
Rating: you need to pull many levers but at least you can. And this makes it a quite useful program to work with. [95%]

Program: Mozilla Mailer (Thunderbird)
Platform: Windows/Linux
Observations: exposes software release and OS in the X-Mailer: header. Creates a message ID with a random stamp and the sender domain – not critical. HELO host-name is your sender-domain. This is acceptable.
Rating: Very usable client for win and linux – Consider using it along with enigmail for PGP integration [90%]

I have chosen for Thunderbird with enigmail, and I am using it ONLY for I2P mail.

Thunderbird Server Settings (POP3)

Thunderbird Outgoing server (SMTP)

I2P router console -> I2PTunnel -> smtp.postman.i2p

I2P router console -> I2PTunnel -> pop3.postman.i2p

It’s workin! Now Installing and configuring enigmail.


Posted on May 4, 2011, in Local and commons, Users and tagged , , , , , . Bookmark the permalink. Leave a comment.

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