From aaf33e220b1412c03b5725abe7cf165c06588fb5 Mon Sep 17 00:00:00 2001
From: Gregor Kleen <gkleen@yggdrasil.li>
Date: Sat, 7 Jun 2025 13:00:03 +0200
Subject: ...

---
 hosts/sif/email/default.nix | 110 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 hosts/sif/email/default.nix

(limited to 'hosts/sif/email/default.nix')

diff --git a/hosts/sif/email/default.nix b/hosts/sif/email/default.nix
new file mode 100644
index 00000000..4eda236e
--- /dev/null
+++ b/hosts/sif/email/default.nix
@@ -0,0 +1,110 @@
+{ config, lib, pkgs, ... }:
+{
+  services.postfix = {
+    enable = true;
+    enableSmtp = false;
+    enableSubmission = false;
+    setSendmail = true;
+    networksStyle = "host";
+    hostname = "sif.midgard.yggdrasil";
+    destination = [];
+    recipientDelimiter = "+";
+    config = {
+      mydomain = "yggdrasil.li";
+
+      local_transport = "error:5.1.1 No local delivery";
+      alias_database = [];
+      alias_maps = [];
+      local_recipient_maps = [];
+
+      inet_interfaces = "loopback-only";
+
+      message_size_limit = "0";
+
+      authorized_submit_users = "inline:{ gkleen= }";
+      authorized_flush_users = "inline:{ gkleen= }";
+      authorized_mailq_users = "inline:{ gkleen= }";
+
+      smtp_generic_maps = "inline:{ root=root+sif }";
+
+      mynetworks = ["127.0.0.0/8" "[::1]/128"];
+      smtpd_client_restrictions = ["permit_mynetworks" "reject"];
+      smtpd_relay_restrictions = ["permit_mynetworks" "reject"];
+
+      sender_dependent_default_transport_maps = ''regexp:${pkgs.writeText "sender_relay" ''
+        /@(cip|stud)\.ifi\.(lmu|uni-muenchen)\.de$/ smtp:smtp.ifi.lmu.de
+        /@ifi\.(lmu|uni-muenchen)\.de$/ smtp:smtpin1.ifi.lmu.de:587
+        /@math(ematik)?\.(lmu|uni-muenchen)\.de$/ smtps:smtp.math.lmu.de:465
+        /@(campus\.)?lmu\.de$/ smtp:postout.lrz.de
+      ''}'';
+      sender_bcc_maps = ''regexp:${pkgs.writeText "sender_bcc" ''
+        /^uni2work(-[^@]*)?@ifi\.lmu\.de$/ uni2work@ifi.lmu.de
+        /@ifi\.lmu\.de$/ gregor.kleen@ifi.lmu.de
+      ''}'';
+      relayhost = "[surtr.yggdrasil.li]:465";
+      default_transport = "relay";
+
+      smtp_sasl_auth_enable = true;
+      smtp_sender_dependent_authentication = true;
+      smtp_sasl_tls_security_options = "noanonymous";
+      smtp_sasl_mechanism_filter = ["plain"];
+      smtp_sasl_password_maps = "regexp:/run/credentials/postfix.service/sasl_passwd";
+      smtp_cname_overrides_servername = false;
+      smtp_always_send_ehlo = true;
+      smtp_tls_security_level = "dane";
+
+      smtp_tls_loglevel = "1";
+      smtp_dns_support_level = "dnssec";
+    };
+    masterConfig = {
+      submission = {
+        type = "inet";
+        private = false;
+        command = "smtpd";
+        args = [
+          "-o" "syslog_name=postfix/$service_name"
+        ];
+      };
+      smtp = { };
+      smtps = {
+        type = "unix";
+        private = true;
+        privileged = true;
+        chroot = false;
+        command = "smtp";
+        args = [
+          "-o" "smtp_tls_wrappermode=yes"
+          "-o" "smtp_tls_security_level=encrypt"
+        ];
+      };
+      relay = {
+        command = "smtp";
+        args = [
+          "-o" "smtp_fallback_relay="
+          "-o" "smtp_tls_security_level=verify"
+          "-o" "smtp_tls_wrappermode=yes"
+          "-o" "smtp_tls_cert_file=${./relay.crt}"
+          "-o" "smtp_tls_key_file=/run/credentials/postfix.service/relay.key"
+        ];
+      };
+    };
+  };
+
+  systemd.services.postfix = {
+    serviceConfig.LoadCredential = [
+      "sasl_passwd:${config.sops.secrets."postfix-sasl-passwd".path}"
+      "relay.key:${config.sops.secrets."relay-key".path}"
+    ];
+  };
+
+  sops.secrets = {
+    postfix-sasl-passwd = {
+      key = "sasl-passwd";
+      sopsFile = ./secrets.yaml;
+    };
+    relay-key = {
+      format = "binary";
+      sopsFile = ./relay.key;
+    };
+  };
+}
-- 
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