360 lines
11 KiB
Markdown
360 lines
11 KiB
Markdown
# ![Simple Nixos MailServer][logo]
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## Stable Releases
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* [SNM v2.0.1](https://github.com/r-raymond/nixos-mailserver/releases/v2.0.1)
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[Latest Release (Candidate)](https://github.com/r-raymond/nixos-mailserver/releases/latest)
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## Features
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### v2.0
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* [x] Continous Integration Testing
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* [x] Multiple Domains
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* Postfix MTA
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- [x] smtp on port 25
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- [x] submission port 587
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- [x] lmtp with dovecot
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* Dovecot
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- [x] maildir folders
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- [x] imap starttls on port 143
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- [x] pop3 starttls on port 110
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* Certificates
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- [x] manual certificates
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- [x] on the fly creation
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- [x] Let's Encrypt
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* Spam Filtering
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- [x] via rspamd
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* Virus Scanning
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- [x] via clamav
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* DKIM Signing
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- [x] via opendkim
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* User Management
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- [x] declarative user management
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- [x] declarative password management
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* Sieves
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- [x] A simple standard script that moves spam
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- [x] Allow user defined sieve scripts
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### In the future
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* User Aliases
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- [ ] More complete alias support (Differentiate between forwarding addresses and sending aliases)
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* DKIM Signing
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- [ ] Allow a per domain selector
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### Changelog
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#### v1.0 -> v1.1
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* Changed structure to Nix Modules
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* Adds Sieve support
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#### v1.1 -> v2.0
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* rename domain to fqdn, seperate fqdn from domains
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* multi domain support
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### Quick Start
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```nix
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{ config, pkgs, ... }:
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{
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imports = [
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(builtins.fetchTarball "https://github.com/r-raymond/nixos-mailserver/archive/v2.0.1.tar.gz")
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];
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mailserver = {
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enable = true;
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fqdn = "mail.example.com";
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domains = [ "example.com" "example2.com" ];
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loginAccounts = {
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"user1@example.com" = {
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hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
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aliases = [
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"info@example.com"
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"postmaster@example.com"
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"postmaster@example2.com"
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];
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};
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};
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};
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}
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```
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For a complete list of options, see `default.nix`.
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## How to Set Up a 10/10 Mail Server Guide
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Mail servers can be a tricky thing to set up. This guide is supposed to run you
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through the most important steps to achieve a 10/10 score on `mail-tester.com`.
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What you need:
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* A server with a public IP (referred to as `server-IP`)
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* A Fully Qualified Domain Name (`FQDN`) where your server is reachable. Note
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so that other servers can find yours. Common FQDN include `mx.example.com`
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(where `example.com` is a domain you own) or `mail.example.com`. The domain
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is referred to as `server-domain` (`example.com` in the above example) and
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the `FQDN` is referred to by `server-FQDN` (`mx.example.com` above).
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* A list of domains you want to your email server to serve. (Note that this
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does not have to include `server-domain`, but may of course). These will be
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referred to as `domains`. As an example, `domains = [ example1.com,
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example2.com ]`.
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### A) Setup server
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The following describes a server setup that is fairly complete. Even though
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there are more possible options (see `default.nix`), these should be the most
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common ones.
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```nix
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{ config, pkgs, ... }:
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{
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imports = [
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(builtins.fetchTarball "https://github.com/r-raymond/nixos-mailserver/archive/v2.0.1.tar.gz")
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];
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mailserver = {
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enable = true;
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fqdn = <server-FQDN>;
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domains = [ <domains> ];
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# A list of all login accounts. To create the password hashes, use
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# mkpasswd -m sha-512 "super secret password"
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loginAccounts = {
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"user1@example.com" = {
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hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
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aliases = [
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"postmaster@example.com"
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"postmaster@example2.com"
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];
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};
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"user2@example.com" = { ... };
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};
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# Extra virtual aliases. These are email addresses that are forwarded to
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# loginAccounts addresses.
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extraVirtualAliases = {
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# address = forward address;
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"abuse@example.com" = "user1@example.com";
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};
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# Use Let's Encrypt certificates. Note that this needs to set up a stripped
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# down nginx and opens port 80.
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certificateScheme = 3;
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# Enable IMAP and POP3
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enableImap = true;
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enablePop3 = true;
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enableImapSsl = true;
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enablePop3Ssl = true;
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# whether to scan inbound emails for viruses (note that this requires at least
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# 1 Gb RAM for the server. Without virus scanning 256 MB RAM should be plenty)
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virusScanning = false;
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};
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}
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```
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After a `nixos-rebuild switch --upgrade` your server should be good to go. If
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you want to use `nixops` to deploy the server, look in the subfolder `nixops`
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for some inspiration.
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### B) Setup everything else
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#### Step 1: Set DNS entry for server
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Add a DNS record to the domain `server-domain` with the following entries
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| Name (Subdomain) | TTL | Type | Priority | Value |
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| ---------------- | ----- | ---- | -------- | ----------------- |
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| `server-FQDN` | 10800 | A | | `server-IP` |
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This resolved DNS equries for `server-FQDN` to `server-IP`. You can test if your
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setting is correct by
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```
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ping <server-FQDN>
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64 bytes from <server-FQDN> (<server-IP>): icmp_seq=1 ttl=46 time=21.3 ms
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...
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```
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Note that it can take a while until a DNS entry is propagated.
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#### Step 2: Set rDNS (reverse DNS) entry for server
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Wherever you have rented your server, you should be able to set reverse DNS
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entries for the IP's you own. Add an entry resolving `server-IP` to
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`server-FQDN`
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You can test if your setting is correct by
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```
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host <server-IP>
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<server-IP>.in-addr.arpa domain name pointer <server-FQDN>.
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```
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Note that it can take a while until a DNS entry is propagated.
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#### Step 3: Set `MX` Records
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For every `domain` in `domains` do:
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* Add a `MX` record to the domain `domain`
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| Name (Subdomain) | TTL | Type | Priority | Value |
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| ---------------- | ----- | ---- | -------- | ----------------- |
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| `domain` | | MX | 10 | `server-FQDN` |
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You can test this via
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```
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dig -t MX <domain>
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...
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;; ANSWER SECTION:
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<domain> 10800 IN MX 10 <server-FQDN>
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...
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```
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Note that it can take a while until a DNS entry is propagated.
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#### Step 4: Set `SPF` Records
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For every `domain` in `domains` do:
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* Add a `SPF` record to the domain `domain`
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| Name (Subdomain) | TTL | Type | Priority | Value |
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| ---------------- | ----- | ---- | -------- | ----------------- |
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| `domain` | 10800 | TXT | | `v=spf1 ip4:<server-IP> -all` |
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You can check this with `dig -t TXT <domain>` similar to the last section.
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Note that it can take a while until a DNS entry is propagated. If you want to
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use multiple servers for your email handling, don't forget to add all server
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IP's to this list.
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#### Step 5: Set `DKIM` signature
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For every `domain` in `domains` do:
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* Go to your server and navigate to the dkim key directory (by default
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`/var/dkim`. There you will find a public key for any domain in the
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`domain.txt` file. It will look like
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```
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mail._domainkey IN TXT "v=DKIM1; r=postmaster; g=*; k=rsa; p=<really-long-key>" ; ----- DKIM mail for domain.tld
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```
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* Add a `DKIM` record to the domain `domain`
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| Name (Subdomain) | TTL | Type | Priority | Value |
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| ---------------- | ----- | ---- | -------- | ----------------- |
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| mail._domainkey.`domain` | 10800 | TXT | | `v=DKIM1; p=<really-long-key>` |
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You can check this with `dig -t TXT <domain>` similar to the last section.
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Note that it can take a while until a DNS entry is propagated.
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### C) Test your Setup
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Write an email to your aunt (who has been waiting for your reply far too long),
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and sign up for some of the finest newsletters the Internet has.
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Besides that, you can send an email to [mail-tester.com](https://www.mail-tester.com/) and see how you score,
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and let [mxtoolbox.com](http://mxtoolbox.com/) take a look at your setup, but if you followed
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the steps closely then everything should be awesome!
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## How to Backup
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This is really easy. First off you should have a backup of your
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`configuration.nix` file where you have the server config (but that is already
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in a git repository right?)
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Next you need to backup `/var/vmail` or whatever you have specified for the
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option `mailDirectory`. This is where all the mails reside. Good options are a
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cron job with `rsync` or `scp`. But really anything works, as it is simply a
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folder with plenty of files in it. If your backup solution does not preserve the
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owner of the files don't forget to `chown` them to `virtualMail:virtualMail` if you copy
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them back (or whatever you specified as `vmailUserName`, and `vmailGoupName`).
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Finally you can (optionally) make a backup of `/var/dkim` (or whatever you
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specified as `dkimKeyDirectory`). If you should lose those don't worry, new ones
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will be created on the fly. But you will need to repeat step `B)5` and correct
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all the `dkim` keys.
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## How to Test for Development
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You can test the setup via `nixops`. After installation, do
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```
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nixops create nixops/single-server.nix nixops/vbox.nix -d mail
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nixops deploy -d mail
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nixops info -d mail
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```
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You can then test the server via e.g. `telnet`. To log into it, use
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```
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nixops ssh -d mail mailserver
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```
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To test imap manually use
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```
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openssl s_client -host mail.example.com -port 143 -starttls imap
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```
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## A Complete Mail Server Without Moving Parts
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### Used Technologies
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* Nixos
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* Nixpkgs
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* Dovecot
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* Postfix
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* Rmilter
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* Rspamd
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* Clamav
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* Opendkim
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* Pam
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### Features
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* unlimited domain
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* unlimited mail accounts
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* unlimited aliases for every mail account
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* spam and virus checking
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* dkim signing of outgoing emails
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* imap (optionally pop3)
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* startTLS
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### Nonfeatures
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* moving parts
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* SQL databases
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* configurations that need to be made after `nixos-rebuild switch`
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* complicated storage schemes
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* webclients / http-servers
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## Contributors
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* Special thanks to @Infinisil for the module rewrite
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* Special thanks to @jbboehr for multidomain implementation
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* @danbst
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* @phdoerfler
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* @eqyiel
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### Alternative Implementations
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* [NixCloud Webservices](https://github.com/nixcloud/nixcloud-webservices)
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### Credits
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* send mail graphic by [tnp_dreamingmao](https://thenounproject.com/dreamingmao)
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from [TheNounProject](https://thenounproject.com/) is licensed under
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[CC BY 3.0](http://creativecommons.org/~/3.0/)
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* Logo made with [Logomakr.com](https://logomakr.com)
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[logo]: logo/logo.png
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