So I have been thinking now that the MeshChat & VoIP telephone network are up and running, the next important service would be to add an Email service for users across the UKMESH Network.

Email services require 2 main elements. 

  • The ability to send or “relay” emails when someone sends one. 
  • The ability to store incoming messages ready for someone to read them, think of a pigeon hole.


The first is referred to as SMTP (Simple Mail  Transport Protocol) and the second has two options POP3 (Post Office Protocol) & IMAP (Internet Message Access Protocol), although IMAP is really the only one in general use anymore these days.

So all we need is to provide 2 services shown above and we can run an email platform, sounds simple right? Well yes and no, whilst setting up the software to do this is pretty simple, the administration and security aspects are far from simple!

There are lots of free/ open source software around to do both in and outbound email processing. about 80% of the internet email services use something called EXIM and DOVECOT as their SMTP and IMAP services.

But I came across something called CITADEL. It is a fully featured communications platform that can be installed and run on a Linux platform (perfect for a RaspberryPi).

The software is described as a fully featured email and collaboration tool.





Taken from the website.

Citadel is open source, which is good as the aim of this project is to be open source and feely available to as many Amateur Radio operators as possible.

It also looks simple and easy to use without the need for users to install any software or configure any settings! Using just a browser to access a full featured web interface. All you need is your browser.


Packed with features

  • email
  • calendar/scheduling
  • address books
  • bulletin boards (forums)
  • mailing list server
  • instant messaging
  • wiki and blog engines
  • multiple domain support
  • a powerful web interface
  • rss aggregation

Sounds promising, so I took the plunge and installed a working version onto one of the Raspberry Pi’s connected to the UKMESH.ORG Network. 

In just under an hour I have now got a full working email platform.

But it provides much more than just a mail server, all the features shown above are available. For now I will concentrate on building up the email platform, adding all the users so that people can start to send emails across the Network without using the internet.

A username and password are required to access the system but you can view it both on and off the UKMESH Network as I have an internet proxy gateway 


On the MESH, visit http://UKMeshRPI1.local.mesh

From the public internet 
(Obviously this will only work if my internet gateway is live, currently not running this 24/7)


Screen shot of the Citadel Email Inbox.

As you can see from the image above, there are many different features to be explored, but the email is working well. 

Currently, emails can not be sent/received outside of the UKMESH network for security reasons. 

However, without the use of the internet, members of UKMESH.ORG network can now email  other members using the format 


These emails flow across the 5Ghz Amateur Radio Mesh to be picked up whenever the recipient logs in to view their inbox.


I’m very pleased with how easy and quickly this additional service was added to the network. It adds another useful and meaningful aspect of the network and hopefully encourages more Amateur Radio Operators to get a cheap node and join in the fun.