feat(postfix): deploy postfix MTA and rspamd spam filter

- mailgateway namespace with Deployment + HPA (2-6 replicas) - rspamd Deployment + HPA (2-6 replicas) with milter interface - postfix configured to relay inbound mail to stalwart via transport maps - rspamd milter on port 11332 for spam scanning and DKIM signing - DKIM keys stored in Vault at kubernetes/namespace/mailgateway/default/dkim-keys - TLS cert via cert-manager (vault-issuer) for mail.main.unkin.net - rspamd web UI exposed via Traefik Gateway at rspamd.k8s.syd1.au.unkin.net - postfix external LoadBalancer service for inbound MX on port 25 - Add full main.cf and master.cf as ConfigMap resources mounted via subPath - main.cf: relay-only gateway config, texthash: transport maps, rspamd milter - master.cf: standard smtp + submission (587, TLS required) + internal processes - MAILNAME/MY_NETWORKS/MY_DESTINATION env vars kept in sync with main.cf - LOG_TO_STDOUT=1 for k8s log collection
2026-05-24 00:43:56 +10:00
parent cbc2c1cb9f
commit b09cd1628d
20 changed files with 560 additions and 0 deletions
@@ -0,0 +1,47 @@
+# Basic identity — kept in sync with MAILNAME/MY_NETWORKS/MY_DESTINATION env vars
+# so the tozd startup script's postconf calls are no-ops
+myhostname = mail.main.unkin.net
+myorigin = main.unkin.net
+mydestination = localhost.localdomain, localhost
+mynetworks = 127.0.0.0/8 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
+inet_protocols = ipv4
+inet_interfaces = all
+
+# No local delivery — we're a relay-only gateway
+local_transport = error:no local delivery
+alias_maps =
+alias_database =
+
+# Relay inbound mail for these domains to Stalwart
+# texthash: reads plain text without requiring postmap (Alpine has no hash/btree)
+relay_domains = main.unkin.net unkin.net
+transport_maps = texthash:/etc/postfix/transport
+
+# rspamd milter (same namespace — short DNS name resolves)
+smtpd_milters = inet:rspamd:11332
+non_smtpd_milters = inet:rspamd:11332
+milter_default_action = accept
+milter_protocol = 6
+milter_mail_macros = i {mail_addr} {client_addr} {client_name} {auth_authen}
+
+# Inbound TLS (cert from cert-manager Certificate resource)
+smtpd_use_tls = yes
+smtpd_tls_security_level = may
+smtpd_tls_cert_file = /etc/postfix/tls/tls.crt
+smtpd_tls_key_file = /etc/postfix/tls/tls.key
+smtpd_tls_loglevel = 1
+
+# Outbound TLS (opportunistic)
+smtp_tls_security_level = may
+smtp_tls_loglevel = 1
+
+# Message size limit (50 MiB)
+message_size_limit = 52428800
+mailbox_size_limit = 0
+
+# Queue retention
+maximal_queue_lifetime = 5d
+bounce_queue_lifetime = 1d
+
+# Log to stdout for k8s log collection
+maillog_file = /dev/stdout
@@ -0,0 +1,42 @@
+# ==========================================================================
+# service type  private unpriv  chroot  wakeup  maxproc command + args
+#               (yes)   (yes)   (yes)   (never) (100)
+# ==========================================================================
+
+# SMTP inbound (port 25) — runs rspamd milter, relays to Stalwart via transport_maps
+smtp      inet  n       -       n       -       -       smtpd
+
+# Submission (port 587) — TLS required, relay from trusted mynetworks only
+submission inet n       -       n       -       -       smtpd
+  -o syslog_name=postfix/submission
+  -o smtpd_tls_security_level=encrypt
+  -o smtpd_sasl_auth_enable=no
+  -o smtpd_reject_unlisted_recipient=no
+  -o smtpd_relay_restrictions=permit_mynetworks,reject
+  -o milter_macro_daemon_name=ORIGINATING
+
+# Internal postfix processes
+pickup    unix  n       -       n       60      1       pickup
+cleanup   unix  n       -       n       -       0       cleanup
+qmgr      unix  n       -       n       300     1       qmgr
+tlsmgr    unix  -       -       n       1000?   1       tlsmgr
+rewrite   unix  -       -       n       -       -       trivial-rewrite
+bounce    unix  -       -       n       -       0       bounce
+defer     unix  -       -       n       -       0       bounce
+trace     unix  -       -       n       -       0       bounce
+verify    unix  -       -       n       -       1       verify
+flush     unix  n       -       n       1000?   0       flush
+proxymap  unix  -       -       n       -       -       proxymap
+proxywrite unix -       -       n       -       1       proxymap
+smtp      unix  -       -       n       -       -       smtp
+relay     unix  -       -       n       -       -       smtp
+showq     unix  n       -       n       -       -       showq
+error     unix  -       -       n       -       -       error
+retry     unix  -       -       n       -       -       error
+discard   unix  -       -       n       -       -       discard
+local     unix  -       n       n       -       -       local
+virtual   unix  -       n       n       -       -       virtual
+lmtp      unix  -       -       n       -       -       lmtp
+anvil     unix  -       -       n       -       1       anvil
+scache    unix  -       -       n       -       1       scache
+postlog   unix-dgram n  -       n       -       1       postlogd
@@ -0,0 +1,2 @@
+main.unkin.net    smtp:[stalwart.stalwart.svc.cluster.local]:25
+unkin.net         smtp:[stalwart.stalwart.svc.cluster.local]:25
@@ -0,0 +1,13 @@
+enabled = true;
+selector = "mail";
+
+domain {
+    main.unkin.net {
+        privkey = "/etc/rspamd/dkim/private_key";
+        selector = "mail";
+    }
+    unkin.net {
+        privkey = "/etc/rspamd/dkim/private_key";
+        selector = "mail";
+    }
+}
@@ -0,0 +1,2 @@
+extended_spam_headers = true;
+use = ["x-spam-status", "x-spam-score", "authentication-results"];
@@ -0,0 +1,7 @@
+milter = yes;
+bind_socket = "*:11332";
+
+upstream "local" {
+    default = yes;
+    self_scan = yes;
+}