feat: privacy mode

Adds support for hiding IP addresses & hostnames associated with clients sending
authenticated mail in to Postal over SMTP and HTTP

app/controllers/servers_controller.rb

@@ -41,7 +41,7 @@ def create
 
   def update
     extra_params = [:spam_threshold, :spam_failure_threshold, :postmaster_address]
-    extra_params += [:send_limit, :allow_sender, :log_smtp_data, :outbound_spam_threshold, :message_retention_days, :raw_message_retention_days, :raw_message_retention_size] if current_user.admin?
+    extra_params += [:send_limit, :allow_sender, :privacy_mode, :log_smtp_data, :outbound_spam_threshold, :message_retention_days, :raw_message_retention_days, :raw_message_retention_size] if current_user.admin?
     if @server.update(safe_params(*extra_params))
       redirect_to_with_json organization_server_path(organization, @server), notice: "Server settings have been updated"
     else

app/models/incoming_message_prototype.rb

@@ -91,7 +91,7 @@ def raw_message
           content: attachment[:data]
         }
       end
-      mail.header["Received"] = "from #{@source_type} (#{@ip} [#{@ip}]) by Postal with HTTP; #{Time.now.utc.rfc2822}"
+      mail.header["Received"] = Postal::ReceivedHeader.generate(@server, @source_type, @ip, :http)
       mail.to_s
     end
   end

app/models/outgoing_message_prototype.rb

@@ -175,7 +175,7 @@ def raw_message
           content: attachment[:data]
         }
       end
-      mail.header["Received"] = "from #{@source_type} (#{resolved_hostname} [#{@ip}]) by Postal with HTTP; #{Time.now.utc.rfc2822}"
+      mail.header["Received"] = Postal::ReceivedHeader.generate(@server, @source_type, @ip, :http)
       mail.message_id = "<#{@message_id}>"
       mail.to_s
     end
@@ -196,12 +196,4 @@ def create_message(address)
     { id: message.id, token: message.token }
   end
 
-  def resolved_hostname
-    @resolved_hostname ||= begin
-      Resolv.new.getname(@ip)
-    rescue StandardError
-      @ip
-    end
-  end
-
 end

app/views/servers/advanced.html.haml

@@ -19,7 +19,11 @@
           .fieldSet__input
             = f.select :allow_sender, [["No", false], ["Yes - can use Sender header", true]], {}, :class => 'input input--select'
             %p.fieldSet__text If enabled, outgoing messages can use any address in the From header as long as a Sender header is included with an authorized address.
-
+        .fieldSet__field
+          = f.label :privacy_mode, "Privacy mode", :class => 'fieldSet__label'
+          .fieldSet__input
+            = f.select :privacy_mode, [["Disabled", false], ["Enabled", true]], {}, :class => 'input input--select'
+            %p.fieldSet__text If enabled, when Postal adds Received headers to e-mails it will not include IP or hostname information of the client submitting the message.
         .fieldSet__field
           = f.label :log_smtp_data, "Log SMTP data?", :class => 'fieldSet__label'
           .fieldSet__input

db/migrate/20240206173036_add_privacy_mode_to_servers.rb

@@ -0,0 +1,5 @@
+class AddPrivacyModeToServers < ActiveRecord::Migration[6.1]
+  def change
+    add_column :servers, :privacy_mode, :boolean, default: false
+  end
+end

db/schema.rb

@@ -2,24 +2,25 @@
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
 #
-# Note that this schema.rb definition is the authoritative source for your
-# database schema. If you need to create the application database on another
-# system, you should be using db:schema:load, not running all the migrations
-# from scratch. The latter is a flawed and unsustainable approach (the more migrations
-# you'll amass, the slower it'll run and the greater likelihood for issues).
+# This file is the source Rails uses to define your schema when running `bin/rails
+# db:schema:load`. When creating a new database, `bin/rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20_210_727_210_551) do
-  create_table "additional_route_endpoints", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+ActiveRecord::Schema.define(version: 2024_02_06_173036) do
+
+  create_table "additional_route_endpoints", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "route_id"
     t.string "endpoint_type"
     t.integer "endpoint_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
   end
 
-  create_table "address_endpoints", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "address_endpoints", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.string "uuid"
     t.string "address"
@@ -28,7 +29,7 @@
     t.datetime "updated_at", null: false
   end
 
-  create_table "authie_sessions", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "authie_sessions", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "token"
     t.string "browser_id"
     t.integer "user_id"
@@ -57,7 +58,7 @@
     t.index ["user_id"], name: "index_authie_sessions_on_user_id"
   end
 
-  create_table "credentials", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "credentials", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.string "key"
     t.string "type"
@@ -70,7 +71,7 @@
     t.string "uuid"
   end
 
-  create_table "domains", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "domains", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.string "uuid"
     t.string "name"
@@ -99,7 +100,7 @@
     t.index ["uuid"], name: "index_domains_on_uuid", length: 8
   end
 
-  create_table "http_endpoints", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "http_endpoints", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.string "uuid"
     t.string "name"
@@ -116,7 +117,7 @@
     t.integer "timeout"
   end
 
-  create_table "ip_addresses", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "ip_addresses", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "ip_pool_id"
     t.string "ipv4"
     t.string "ipv6"
@@ -126,7 +127,7 @@
     t.integer "priority"
   end
 
-  create_table "ip_pool_rules", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "ip_pool_rules", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "uuid"
     t.string "owner_type"
     t.integer "owner_id"
@@ -137,7 +138,7 @@
     t.datetime "updated_at", null: false
   end
 
-  create_table "ip_pools", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "ip_pools", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "name"
     t.string "uuid"
     t.datetime "created_at", precision: 6
@@ -146,14 +147,14 @@
     t.index ["uuid"], name: "index_ip_pools_on_uuid", length: 8
   end
 
-  create_table "organization_ip_pools", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "organization_ip_pools", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "organization_id"
     t.integer "ip_pool_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
   end
 
-  create_table "organization_users", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "organization_users", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "organization_id"
     t.integer "user_id"
     t.datetime "created_at", precision: 6
@@ -162,7 +163,7 @@
     t.string "user_type"
   end
 
-  create_table "organizations", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "organizations", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "uuid"
     t.string "name"
     t.string "permalink"
@@ -178,7 +179,7 @@
     t.index ["uuid"], name: "index_organizations_on_uuid", length: 8
   end
 
-  create_table "queued_messages", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "queued_messages", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.integer "message_id"
     t.string "domain"
@@ -197,7 +198,7 @@
     t.index ["server_id"], name: "index_queued_messages_on_server_id"
   end
 
-  create_table "routes", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "routes", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "uuid"
     t.integer "server_id"
     t.integer "domain_id"
@@ -212,7 +213,7 @@
     t.index ["token"], name: "index_routes_on_token", length: 6
   end
 
-  create_table "servers", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "servers", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "organization_id"
     t.string "uuid"
     t.string "name"
@@ -240,13 +241,14 @@
     t.text "domains_not_to_click_track"
     t.string "suspension_reason"
     t.boolean "log_smtp_data", default: false
+    t.boolean "privacy_mode", default: false
     t.index ["organization_id"], name: "index_servers_on_organization_id"
     t.index ["permalink"], name: "index_servers_on_permalink", length: 6
     t.index ["token"], name: "index_servers_on_token", length: 6
     t.index ["uuid"], name: "index_servers_on_uuid", length: 8
   end
 
-  create_table "smtp_endpoints", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "smtp_endpoints", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.string "uuid"
     t.string "name"
@@ -260,13 +262,13 @@
     t.datetime "updated_at", precision: 6
   end
 
-  create_table "statistics", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "statistics", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.bigint "total_messages", default: 0
     t.bigint "total_outgoing", default: 0
     t.bigint "total_incoming", default: 0
   end
 
-  create_table "track_certificates", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "track_certificates", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "domain"
     t.text "certificate"
     t.text "intermediaries"
@@ -280,7 +282,7 @@
     t.index ["domain"], name: "index_track_certificates_on_domain", length: 8
   end
 
-  create_table "track_domains", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "track_domains", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "uuid"
     t.integer "server_id"
     t.integer "domain_id"
@@ -296,7 +298,7 @@
     t.text "excluded_click_domains"
   end
 
-  create_table "user_invites", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "user_invites", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "uuid"
     t.string "email_address"
     t.datetime "expires_at", precision: 6
@@ -305,7 +307,7 @@
     t.index ["uuid"], name: "index_user_invites_on_uuid", length: 12
   end
 
-  create_table "users", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "users", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "uuid"
     t.string "first_name"
     t.string "last_name"
@@ -323,14 +325,14 @@
     t.index ["uuid"], name: "index_users_on_uuid", length: 8
   end
 
-  create_table "webhook_events", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "webhook_events", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "webhook_id"
     t.string "event"
     t.datetime "created_at", precision: 6
     t.index ["webhook_id"], name: "index_webhook_events_on_webhook_id"
   end
 
-  create_table "webhook_requests", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "webhook_requests", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.integer "webhook_id"
     t.string "url"
@@ -343,7 +345,7 @@
     t.datetime "created_at", precision: 6
   end
 
-  create_table "webhooks", id: :integer, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4", force: :cascade do |t|
+  create_table "webhooks", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "server_id"
     t.string "uuid"
     t.string "name"
@@ -356,4 +358,5 @@
     t.datetime "updated_at", precision: 6
     t.index ["server_id"], name: "index_webhooks_on_server_id"
   end
+
 end

lib/postal/received_header.rb

@@ -0,0 +1,43 @@
+module Postal
+  class ReceivedHeader
+
+    OUR_HOSTNAMES = {
+      smtp: Postal.config.dns.smtp_server_hostname,
+      http: Postal.config.web.host
+    }
+
+    class << self
+
+      def generate(server, helo, ip_address, method)
+        our_hostname = OUR_HOSTNAMES[method]
+        if our_hostname.nil?
+          raise Error, "`method` is invalid (must be one of #{OUR_HOSTNAMES.join(', ')})"
+        end
+
+        header = "by #{our_hostname} with #{method.to_s.upcase}; #{Time.now.utc.rfc2822}"
+
+        if server.nil? || server.privacy_mode == false
+          hostname = resolve_hostname(ip_address)
+          header = "from #{helo} (#{hostname} [#{ip_address}]) #{header}"
+        end
+
+        header
+      end
+
+      private
+
+      def resolve_hostname(ip_address)
+        Resolv::DNS.open do |dns|
+          dns.timeouts = [10, 5]
+          begin
+            dns.getname(ip_address)
+          rescue StandardError
+            ip_address
+          end
+        end
+      end
+
+    end
+
+  end
+end

lib/postal/smtp_server/client.rb

@@ -103,17 +103,6 @@ def log(text)
 
       private
 
-      def resolve_hostname
-        Resolv::DNS.open do |dns|
-          dns.timeouts = [10, 5]
-          @hostname = begin
-            dns.getname(@ip_address)
-          rescue StandardError
-            @ip_address
-          end
-        end
-      end
-
       def proxy(data)
         if m = data.match(/\APROXY (.+) (.+) (.+) (.+) (.+)\z/)
           @ip_address = m[2]
@@ -143,15 +132,13 @@ def starttls
       end
 
       def ehlo(data)
-        resolve_hostname
         @helo_name = data.strip.split(" ", 2)[1]
         transaction_reset
         @state = :welcomed
         ["250-My capabilities are", Postal.config.smtp_server.tls_enabled? && !@tls ? "250-STARTTLS" : nil, "250 AUTH CRAM-MD5 PLAIN LOGIN"]
       end
 
       def helo(data)
-        resolve_hostname
         @helo_name = data.strip.split(" ", 2)[1]
         transaction_reset
         @state = :welcomed
@@ -377,10 +364,10 @@ def data(data)
         @headers = {}
         @receiving_headers = true
 
-        received_header_content = "from #{@helo_name} (#{@hostname} [#{@ip_address}]) by #{Postal.config.dns.smtp_server_hostname} with SMTP; #{Time.now.utc.rfc2822}".force_encoding("BINARY")
-        unless Postal.config.smtp_server.strip_received_headers?
-          @data << "Received: #{received_header_content}\r\n"
-        end
+        received_header = Postal::ReceivedHeader.generate(@credential&.server, @helo_name, @ip_address, :smtp)
+                                                .force_encoding("BINARY")
+
+        @data << "Received: #{received_header_content}\r\n"
         @headers["received"] = [received_header_content]
 
         handler = proc do |data|