diff --git a/hieradata/country/au/region/syd1/infra/halb/haproxy2.yaml b/hieradata/country/au/region/syd1/infra/halb/haproxy2.yaml
index eaff76b..66e37a6 100644
--- a/hieradata/country/au/region/syd1/infra/halb/haproxy2.yaml
+++ b/hieradata/country/au/region/syd1/infra/halb/haproxy2.yaml
@@ -13,8 +13,7 @@ profiles::haproxy::dns::vrrp_cnames:
   - dashboard.ceph.unkin.net
   - mail-webadmin.main.unkin.net
   - mail-in.main.unkin.net
-  - imap.main.unkin.net
-  - imaps.main.unkin.net
+  - mail.main.unkin.net
   - autoconfig.main.unkin.net
   - autodiscover.main.unkin.net
 
@@ -333,7 +332,7 @@ profiles::haproxy::backends:
       stick-table: 'type ip size 200k expire 30m'
       stick: 'on src'
       tcp-check:
-        - connect port 143
+        - connect port 143 send-proxy
         - expect string "* OK"
         - send "A001 STARTTLS\r\n"
         - expect rstring "A001 (OK|2.0.0)"
@@ -349,7 +348,7 @@ profiles::haproxy::backends:
       stick-table: 'type ip size 200k expire 30m'
       stick: 'on src'
       tcp-check:
-        - connect ssl
+        - connect ssl send-proxy
         - expect string "* OK"
   be_stalwart_smtp:
     description: Backend for Stalwart SMTP
@@ -363,7 +362,21 @@ profiles::haproxy::backends:
       stick-table: 'type ip size 200k expire 30m'
       stick: 'on src'
       tcp-check:
-        - connect port 25
+        - connect port 25 send-proxy
+        - expect string "220 "
+  be_stalwart_submission:
+    description: Backend for Stalwart SMTP Submission
+    collect_exported: false
+    options:
+      mode: tcp
+      balance: roundrobin
+      option:
+        - tcp-check
+        - prefer-last-server
+      stick-table: 'type ip size 200k expire 30m'
+      stick: 'on src'
+      tcp-check:
+        - connect port 587 send-proxy
         - expect string "220 "
 
 profiles::haproxy::certlist::enabled: true
diff --git a/hieradata/roles/infra/halb/haproxy2.yaml b/hieradata/roles/infra/halb/haproxy2.yaml
index f58be10..10d19c6 100644
--- a/hieradata/roles/infra/halb/haproxy2.yaml
+++ b/hieradata/roles/infra/halb/haproxy2.yaml
@@ -196,6 +196,17 @@ profiles::haproxy::frontends:
       tcp-request:
         - inspect-delay 5s
         - content accept if { req_len 0 }
+  fe_submission:
+    description: 'Frontend for Stalwart SMTP Submission'
+    bind:
+      0.0.0.0:587: []
+    mode: 'tcp'
+    options:
+      log: global
+      default_backend: be_stalwart_submission
+      tcp-request:
+        - inspect-delay 5s
+        - content accept if { req_len 0 }
 
 profiles::haproxy::backends:
   be_letsencrypt:
diff --git a/hieradata/roles/infra/mail/backend.yaml b/hieradata/roles/infra/mail/backend.yaml
index ae937b0..c26c200 100644
--- a/hieradata/roles/infra/mail/backend.yaml
+++ b/hieradata/roles/infra/mail/backend.yaml
@@ -8,9 +8,6 @@ hiera_include:
 profiles::pki::vault::alt_names:
   - mail.main.unkin.net
   - mail-webadmin.main.unkin.net
-  - imap.main.unkin.net
-  - imaps.main.unkin.net
-  - smtp.main.unkin.net
   - main-in.main.unkin.net
   - autoconfig.main.unkin.net
   - autodiscovery.main.unkin.net
@@ -41,6 +38,7 @@ stalwart::s3_region: "%{facts.region}"
 stalwart::domains:
   - 'mail.unkin.net'
 stalwart::postfix_relay_host: 'out-mta.main.unkin.net'
+stalwart::service_hostname: 'mail.main.unkin.net'
 stalwart::manage_dns_records: false
 
 ## With load balancer:
diff --git a/modules/stalwart/manifests/config.pp b/modules/stalwart/manifests/config.pp
index 2b43ea5..95aa763 100644
--- a/modules/stalwart/manifests/config.pp
+++ b/modules/stalwart/manifests/config.pp
@@ -29,6 +29,7 @@ class stalwart::config {
     content => epp('stalwart/config.toml.epp', {
       'cluster_size'            => $stalwart::cluster_size,
       'other_cluster_members'   => $stalwart::other_cluster_members,
+      'haproxy_ips'             => $stalwart::haproxy_ips,
       'effective_node_id'       => $stalwart::effective_node_id,
       'bind_address'            => $stalwart::bind_address,
       'advertise_address'       => $stalwart::advertise_address,
@@ -49,10 +50,12 @@ class stalwart::config {
       'enable_imap'             => $stalwart::enable_imap,
       'enable_imap_tls'         => $stalwart::enable_imap_tls,
       'enable_http'             => $stalwart::enable_http,
+      'enable_smtp_submission'  => $stalwart::enable_smtp_submission,
       'data_dir'                => $stalwart::data_dir,
       'tls_cert'                => $stalwart::tls_cert,
       'tls_key'                 => $stalwart::tls_key,
       'log_level'               => $stalwart::log_level,
+      'service_hostname'        => $stalwart::service_hostname,
       'fallback_admin_user'     => $stalwart::fallback_admin_user,
       'fallback_admin_password' => $stalwart::fallback_admin_password,
       'webadmin_unpack_path'    => $stalwart::webadmin_unpack_path,
diff --git a/modules/stalwart/manifests/init.pp b/modules/stalwart/manifests/init.pp
index 27b2671..093e960 100644
--- a/modules/stalwart/manifests/init.pp
+++ b/modules/stalwart/manifests/init.pp
@@ -86,6 +86,15 @@
 # @param enable_smtp_relay
 #   Enable SMTP for postfix relay communication
 #
+# @param enable_smtp_submission
+#   Enable SMTP submission listener on port 587
+#
+# @param haproxy_role
+#   Role name for HAProxy nodes to include in proxy trusted networks
+#
+# @param service_hostname
+#   Service hostname used for autoconfig/autodiscover and SMTP greeting
+#
 # @param package_ensure
 #   Package version to install
 #
@@ -133,6 +142,9 @@ class stalwart (
   Boolean                   $enable_imap_tls         = true,
   Boolean                   $enable_http             = true,
   Boolean                   $enable_smtp_relay       = true,
+  Boolean                   $enable_smtp_submission  = true,
+  String                    $haproxy_role            = 'roles::infra::halb::haproxy2',
+  Stdlib::Fqdn              $service_hostname        = $facts['networking']['fqdn'],
   String                    $package_ensure          = 'present',
   Stdlib::Absolutepath      $config_dir              = '/opt/stalwart/etc',
   Stdlib::Absolutepath      $data_dir                = '/var/lib/stalwart',
@@ -166,6 +178,14 @@ class stalwart (
   $other_cluster_members = $sorted_cluster_members.filter |$member| { $member != $my_fqdn }
   $cluster_size = length($sorted_cluster_members)
 
+  # Query HAProxy nodes for proxy trusted networks
+  $haproxy_query = "enc_role='${haproxy_role}' and country='${facts['country']}' and region='${facts['region']}'"
+  $haproxy_members_raw = query_nodes($haproxy_query, 'networking.ip')
+  $haproxy_ips = $haproxy_members_raw ? {
+    undef   => [],
+    default => sort($haproxy_members_raw),
+  }
+
   # Extract last 4 digits from hostname (e.g., ausyd1nxvm1234 -> 1234)
   if $hostname =~ /^.*(\d{4})$/ {
     $hostname_digits = $1
diff --git a/modules/stalwart/templates/config.toml.epp b/modules/stalwart/templates/config.toml.epp
index 83c2c14..b432dea 100644
--- a/modules/stalwart/templates/config.toml.epp
+++ b/modules/stalwart/templates/config.toml.epp
@@ -2,7 +2,7 @@
 # Generated by Puppet - DO NOT EDIT MANUALLY
 
 [server]
-hostname = "<%= $node_facts['networking']['fqdn'] %>"
+hostname = "<%= $service_hostname %>"
 greeting = "Stalwart ESMTP"
 
 [server.listener."smtp-relay"]
@@ -10,10 +10,33 @@ bind = ["<%= $bind_address %>:25"]
 protocol = "smtp"
 greeting = "Stalwart SMTP Relay"
 
+<% if !$haproxy_ips.empty { -%>
+[server.listener."smtp-relay".proxy]
+trusted-networks = ["127.0.0.0/8", "::1"<% $haproxy_ips.each |$ip| { %>, "<%= $ip %>"<% } %>]
+<% } -%>
+
+<% if $enable_smtp_submission { -%>
+[server.listener."submission"]
+bind = ["<%= $bind_address %>:587"]
+protocol = "smtp"
+greeting = "Stalwart SMTP Submission"
+tls.require = true
+
+<% if !$haproxy_ips.empty { -%>
+[server.listener."submission".proxy]
+trusted-networks = ["127.0.0.0/8", "::1"<% $haproxy_ips.each |$ip| { %>, "<%= $ip %>"<% } %>]
+<% } -%>
+<% } -%>
+
 <% if $enable_imap { -%>
 [server.listener."imap"]
 bind = ["<%= $bind_address %>:143"]
 protocol = "imap"
+
+<% if !$haproxy_ips.empty { -%>
+[server.listener."imap".proxy]
+trusted-networks = ["127.0.0.0/8", "::1"<% $haproxy_ips.each |$ip| { %>, "<%= $ip %>"<% } %>]
+<% } -%>
 <% } -%>
 
 <% if $enable_imap_tls { -%>
@@ -21,6 +44,11 @@ protocol = "imap"
 bind = ["<%= $bind_address %>:993"]
 protocol = "imap"
 tls.implicit = true
+
+<% if !$haproxy_ips.empty { -%>
+[server.listener."imaps".proxy]
+trusted-networks = ["127.0.0.0/8", "::1"<% $haproxy_ips.each |$ip| { %>, "<%= $ip %>"<% } %>]
+<% } -%>
 <% } -%>
 
 <% if $enable_http { -%>
@@ -28,6 +56,11 @@ tls.implicit = true
 bind = ["<%= $bind_address %>:443"]
 protocol = "http"
 tls.implicit = true
+
+<% if !$haproxy_ips.empty { -%>
+[server.listener."https".proxy]
+trusted-networks = ["127.0.0.0/8", "::1"<% $haproxy_ips.each |$ip| { %>, "<%= $ip %>"<% } %>]
+<% } -%>
 <% } -%>
 
 [server.tls]
@@ -35,6 +68,7 @@ enable = true
 implicit = false
 certificate = "default"
 
+
 [webadmin]
 path = "<%= $webadmin_unpack_path %>"
 auto-update = <%= $webadmin_auto_update %>
@@ -167,6 +201,12 @@ directory = "internal"
 [imap.protocol]
 max-requests = 64
 
+# Inbound rate limiting
+[[queue.limiter.inbound]]
+key = ["remote_ip"]
+rate = "500/1s"
+enable = true
+
 # SMTP configuration for postfix relay
 [session.data]
 pipe.command = "sendmail"
@@ -212,6 +252,7 @@ max-message-size = 52428800
 [certificate."default"]
 cert = "%{file:<%= $tls_cert %>}%"
 private-key = "%{file:<%= $tls_key %>}%"
+default = true
 
 # Logging configuration
 [tracer]
diff --git a/site/profiles/manifests/stalwart/haproxy.pp b/site/profiles/manifests/stalwart/haproxy.pp
index e8375e9..82a3734 100644
--- a/site/profiles/manifests/stalwart/haproxy.pp
+++ b/site/profiles/manifests/stalwart/haproxy.pp
@@ -15,6 +15,7 @@ class profiles::stalwart::haproxy (
       'inter 2s',
       'rise 3',
       'fall 2',
+      'send-proxy-v2',
     ]
   }
 
@@ -27,6 +28,7 @@ class profiles::stalwart::haproxy (
       'inter 3s',
       'rise 2',
       'fall 3',
+      'send-proxy-v2',
     ]
   }
 
@@ -41,6 +43,7 @@ class profiles::stalwart::haproxy (
       'inter 3s',
       'rise 2',
       'fall 3',
+      'send-proxy-v2',
     ]
   }
 
@@ -53,6 +56,20 @@ class profiles::stalwart::haproxy (
       'inter 3s',
       'rise 2',
       'fall 3',
+      'send-proxy-v2',
+    ]
+  }
+
+  # smtp submission
+  profiles::haproxy::balancemember { "${facts['networking']['fqdn']}_587":
+    service => 'be_stalwart_submission',
+    ports   => [587],
+    options => [
+      'check',
+      'inter 3s',
+      'rise 2',
+      'fall 3',
+      'send-proxy-v2',
     ]
   }