Mixmaster on a Raspberry Pi

Echolot Overview

Echolot sends Mixmaster messages to remailers in order to measure their reliability. It also collects and publishes remailer keys that users require to create Mixmaster messages.

Echolot Login

Whether you're logging into your Pi locally or via SSH, the user account to use is called "maint". Hopefully you have created a strong password for it, as described in the previous steps, or better still, restricted it to key login.

Once you've logged in as "maint", you can switch to the Echolot account using this command:

su - echolot

You will be prompted for the echolot account password that you set earlier. Enter that and you will switch from the 'maint' user to the 'echolot' user. Try to remember the su command, it's fundamental to switching between the various accounts on any Linux system.


The echolot configuration file can be found in echolot/pingd.conf. The basic changes required to customize it for your location are:

Setting Description
sitename The name you'd like for the Pinger. Any text name is acceptable.
my_domain The domain name of your Raspberry Pi. Your earlier postfix configuration should deliver email to this domain.
operator_address An email address for a human, probably you, who is the Echolot operator.

Now logout of the echolot user account, your work on it is complete.


The 'exit' command is another you need to remember. It logs you out of the current account. As you used 'su' to switch from 'maint' to 'echolot', you should now be 'maint' once more.

Starting Services

Now your Echolot service is configured, it needs to be started. The 'maint' user has the authority to do this using the following command:

sudo systemctl start echolot

If echolot starts without any issues, you can safely tell your OS to start it after every reboot:

sudo systemctl enable echolot

When Echolot started, it will have created the 'results' directory that can be published via a webserver. You Pi has a webserver called nginx installed so that can also now be started and enabled.

sudo systemctl start nginx
sudo systemctl enable nginx

You should now be able to point a browser at http://www.your.domain/echolot to view stats. Your Mixmaster remailer will also use these stats but isn't reliant on the webserver publishing them, instead accessing them directly through the filesystem.

Populating Echolot with Remailers

Your pinger is now running but it doesn't know about any Remailers. You have to tell it which Remailers you'd like it to ping. There is a script included on your Pi that will tell it about all the remailers that were known at the time the image was made.

Using the 'su' command, switch back to the echolot user and issue this command:


This will recursively tell Echolot to add each of the remailers in a pre-built list.

With Echolot running and populated, it will take a few hours to gather meaningful stats from the various Remailers. It's best to wait until it publishes this info before moving on to starting Mixmaster.