maddy
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Brian Picciano
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description: >-
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This blog is no longer sponsored by Microsoft!
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tags: tech
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series: selfhost
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---
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Slowly but surely I'm working on moving my digital life back to being
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---
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title: >-
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Self-Hosted Email With maddy: A Naive First Attempt
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description: >-
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How hard could it be?
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tags: tech
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series: selfhost
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---
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For a _long_ time now I've wanted to get off gmail and host my own email
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domains. I've looked into it a few times, but have been discouraged on multiple
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fronts:
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* Understanding the protocols underlying email isn't straightforward; it's an
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old system, there's a lot of cruft, lots of auxiliary protocols that are now
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essentially required, and a lot of different services required to tape it all
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together.
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* The services which are required are themselves old, and use operational
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patterns that maybe used to make sense but are now pretty freaking cumbersome.
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For example, postfix requires something like 3 different system accounts.
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* Deviating from the non-standard route and using something like
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[Mail-in-a-box][miab] involves running docker, which I'm trying to avoid.
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So up till now I had let the idea sit, waiting for something better to come
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along.
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[maddy][maddy] is, I think, something better. According to the homepage
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"\[maddy\] replaces Postfix, Dovecot, OpenDKIM, OpenSPF, OpenDMARC and more with
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one daemon with uniform configuration and minimal maintenance cost." Sounds
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perfect! The homepage is clean and to the point, it's written in go, and the
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docs appear to be reasonably well written. And, to top it all off, it's already
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been added to [nixpkgs][nixpkgs]!
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So in this post (and subsequent posts) I'll be documenting my journey into
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getting a maddy server running to see how well it works out.
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## Just Do It
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I'm almost 100% sure this won't work, but to start with I'm going to simply get
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maddy up and running on my home media server as per the tutorial on its site,
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and go from there.
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First there's some global system configuration I need to perform. Ideally maddy
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could be completely packaged up and not pollute the rest of the system at all,
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and if I was using NixOS I think that would be possible, but as it is I need to
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create a user for maddy and ensure it's able to read the TLS certificates that I
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manage via [LetsEncrypt][le].
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```bash
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sudo useradd -mrU -s /sbin/nologin -d /var/lib/maddy -c "maddy mail server" maddy
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sudo setfacl -R -m u:maddy:rX /etc/letsencrypt/{live,archive}
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```
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The next step is to set up the nix build of the systemd service file. This is a
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strategy I've been using recently to nix-ify my services without needing to deal
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with nix profiles. The idea is to encode the nix store path to everything
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directly into the systemd service file, and install that file normally. In this
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case this looks something like:
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```
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pkgs.writeTextFile {
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name = "mediocregopher-maddy-service";
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text = ''
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[Unit]
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Description=mediocregopher maddy
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Documentation=man:maddy(1)
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Documentation=man:maddy.conf(5)
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Documentation=https://maddy.email
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After=network.target
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[Service]
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Type=notify
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NotifyAccess=main
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Restart=always
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RestartSec=1s
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User=maddy
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Group=maddy
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# cd to state directory to make sure any relative paths
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# in config will be relative to it unless handled specially.
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WorkingDirectory=/mnt/vol1/maddy
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ReadWritePaths=/mnt/vol1/maddy
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# ... lots of directives from
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# https://github.com/foxcpp/maddy/blob/master/dist/systemd/maddy.service
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# that we'll elide here ...
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ExecStart=${pkgs.maddy}/bin/maddy -config ${./maddy.conf}
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ExecReload=/bin/kill -USR1 $MAINPID
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ExecReload=/bin/kill -USR2 $MAINPID
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[Install]
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WantedBy=multi-user.target
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'';
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}
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```
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With the service now testable, it falls on me to actually go through the setup
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steps described in the [tutorial][tutorial].
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## Following The Tutorial
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The first step in the tutorial is setting up of domain names, which I first
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perform in cloudflare (where my DNS is hosted) and then reflect into the conf
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file. Then I point the `tls file` configuration line at my LetsEncrypt
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directory by changing the line to:
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```
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tls file /etc/letsencrypt/live/$(hostname)/fullchain.pem /etc/letsencrypt/live/$(hostname)/privkey.pem
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```
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maddy can access these files thanks to the `setfacl` command I performed
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earlier.
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At this point the server should be effectively configured. However, starting it
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via systemd results in this error:
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```
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failed to load /etc/letsencrypt/live/mx.mydomain.com/fullchain.pem and /etc/letsencrypt/live/mx.mydomain.com/privkey.pem
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```
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(For my own security I'm not going to be using the actual email domain in this
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post, I'll use `mydomain.com` instead.)
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This makes sense... I use a wildcard domain with LetsEncrypt, so certs for the
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`mx` sub-domain specifically won't exist. I need to figure out how to tell maddy
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to use the wildcard, or actually create a separate certificate for the `mx`
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sub-domain. I'd rather the former, obviously, as it's far less work.
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Luckily, making it use the wildcard isn't too hard, all that is needed is to
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change the `tls file` line to:
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```
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tls file /etc/letsencrypt/live/$(primary_domain)/fullchain.pem /etc/letsencrypt/live/$(primary_domain)/privkey.pem
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```
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This works because my `primary_domain` domain is set to the top-level
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(`mydomain.com`), which is what the wildcard cert is issued for.
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At this point maddy is up and running, but there's still a slight problem. maddy
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appears to be placing all of its state files in `/var/lib/maddy`, even though
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I'd like to place them in `/mnt/vol1/maddy`. I had set the `WorkingDirectory` in
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the systemd service file to this, but apparently that's not enough. After
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digging through the codebase I discover an undocumented directive which can be
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added to the conf file:
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```
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state_dir /mnt/vol1/maddy
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```
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Kind of annoying, but at least it works.
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The next step is to fiddle with DNS records some more. I add the SPF, DMARC and
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DKIM records to cloudflare as described by the tutorial (what do these do? I
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have no fuckin clue).
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I also need to set up MTA-STS (again, not really knowing what that is). The
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tutorial says I need to make a file with certain contents available at the URL
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`https://mta-sts.mydomain.com/.well-known/mta-sts.txt`. I love it when protocol
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has to give up and resort to another one in order to keep itself afloat, it
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really inspires confidence.
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Anyway, I set that subdomain up in cloudflare, and add the following to my nginx
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configuration:
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```
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server {
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listen 80;
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server_name mta-sts.mydomain.com;
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include include/public_whitelist.conf;
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location / {
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return 404;
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}
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location /.well-known/mta-sts.txt {
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# Check out openresty if you want to get super useful nginx plugins, like
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# the echo module, out-of-the-box.
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echo 'mode: enforce';
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echo 'max_age: 604800';
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echo 'mx: mx.mydomain.com';
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}
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}
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```
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(Note: my `public_whitelist.conf` only allows cloudflare IPs to access this
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sub-domain, which is something I do for all sub-domains which I can put through
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cloudflare.)
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Finally, I need to create some actual credentials in maddy with which to send my
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email. I do this via the `maddyctl` command-line utility:
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```
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> sudo maddyctl --config maddy.conf creds create 'me@mydomain.com'
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Enter password for new user:
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> sudo maddyctl --config maddy.conf imap-acct create 'me@mydomain.com'
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```
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## Send It!
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At this point I'm ready to actually test the email sending. I'm going to use
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[S-nail][snail] to do so, and after reading through the docs there I put the
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following in my `~/.mailrc`:
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```
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set v15-compat
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set mta=smtp://me%40mydomain.com:password@localhost:587 smtp-use-starttls
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```
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And attempt the following `mailx` command to send an email from my new mail
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server:
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```
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> echo 'Hello! This is a cool email' | mailx -s 'Subject' -r 'Me <me@mydomain.com>' 'test.email@gmail.com'
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reproducible_build: TLS certificate does not match: localhost:587
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/home/mediocregopher/dead.letter 10/313
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reproducible_build: ... message not sent
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```
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Damn. TLS is failing because I'm connecting over `localhost`, but maddy is
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serving the TLS certs for `mydomain.com`. Since I haven't gone through the steps
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of exposing maddy publicly yet (which would require port forwarding in my
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router, as well as opening a port in iptables) I can't properly test this with
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TLS not being required. _It's very important that I remember to re-require TLS
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before putting anything public._
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In the meantime I remove the `smtp-use-starttls` entry from my `~/.mailrc`, and
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retry the `mailx` command. This time I get a different error:
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```
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reproducible_build: SMTP server: 523 5.7.10 TLS is required
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```
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It turns out there's a further configuration directive I need to add, this time
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in `maddy.conf`. Within my `submission` configuration block I add the following
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line:
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```
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insecure_auth true
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```
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This allows plaintext auth over non-TLS connections. Kind of sketchy, but again
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I'll undo this before putting anything public.
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Finally, I try the `mailx` command one more time, and it successfully returns!
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Unfortunately, no email is ever received in my gmail :( I check the maddy logs
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and see what I feared most all along:
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```
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Jun 29 08:44:58 maddy[127396]: remote: cannot use MX {"domain":"gmail.com","io_op":"dial","msg_id":"5c23d76a-60db30e7","reason":"dial tcp 142.250.152.26:25: connect: connection timed out","remote_addr":"142.250.152.
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26:25","remote_server":"alt1.gmail-smtp-in.l.google.com.","smtp_code":450,"smtp_enchcode":"4.4.2","smtp_msg":"Network I/O error"}
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```
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My ISP is blocking outbound connections on port 25. This is classic email
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bullshit; ISPs essentially can't allow outbound SMTP connections, as email is so
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easily abusable it would drastically increase the amount of spam being sent from
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their networks.
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## Lessons Learned
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The next attempt will involve an external VPS which allows SMTP, and a lot more
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interesting configuration. But for now I'm forced to turn off maddy and let this
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dream sit for a little while longer.
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[miab]: https://mailinabox.email/
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[maddy]: https://maddy.email
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[nixpkgs]: https://search.nixos.org/packages?channel=21.05&from=0&size=50&sort=relevance&query=maddy
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[tutorial]: https://maddy.email/tutorials/setting-up/
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[le]: https://letsencrypt.org/
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[snail]: https://wiki.archlinux.org/title/S-nail
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