Mailfromd Manual

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Mailfromd

This edition of the Mailfromd Manual, last updated 11 December 2025, documents mailfromd Version 9.1.

Table of Contents

Preface
- Short history of mailfromd.
- Acknowledgments
1 Introduction to mailfromd
- 1.1 Typographical conventions
- 1.2 Overview of Mailfromd
- 1.3 Sender Address Verification.
  - 1.3.1 Limitations of Sender Address Verification
- 1.4 Controlling Mail Sending Rate.
- 1.5 SPF, DKIM, and others
2 Building the Package
3 Tutorial
- 3.1 Start Up
- 3.2 Simplest Configurations
- 3.3 Conditional Execution
- 3.4 Functions and Modules
- 3.5 Domain Name System
- 3.6 Checking Sender Address
- 3.7 SMTP Timeouts
- 3.8 Avoiding Verification Loops
- 3.9 HELO Domain
- 3.10 SMTP RSET and Milter Abort Handling
- 3.11 Controlling Number of Recipients
- 3.12 Sending Rate
- 3.13 Greylisting
- 3.14 Local Account Verification
- 3.15 Databases
  - 3.15.1 Database Formats
  - 3.15.2 Basic Database Operations
  - 3.15.3 Database Maintenance
- 3.16 Testing Filter Scripts
- 3.17 Run Mode
  - 3.17.1 The Top of a Script File
  - 3.17.2 Parsing Command Line Arguments
- 3.18 Examining Default Values
- 3.19 Logging and Debugging
- 3.20 Runtime Errors
- 3.21 Notes and Cautions
4 Mail Filtering Language
- 4.1 Comments
- 4.2 #include and #include_once
- 4.3 #line
- 4.4 #warning and #error
- 4.5 Pragmatic comments
  - 4.5.1 Pragma prereq
  - 4.5.2 Pragma stacksize
  - 4.5.3 Pragma regex
  - 4.5.4 Pragma dbprop
  - 4.5.5 Pragma greylist
  - 4.5.6 Pragma miltermacros
  - 4.5.7 Pragma provide-callout
- 4.6 Data Types
- 4.7 Numbers
- 4.8 Literals
- 4.9 Here Documents
- 4.10 Sendmail Macros
- 4.11 Constants
  - 4.11.1 Built-in constants
- 4.12 Variables
  - 4.12.1 Predefined Variables
- 4.13 Back references
- 4.14 Handlers
  - 4.14.1 Multiple Handler Definitions
- 4.15 Initialization and Cleanup Handlers
  - 4.15.1 The ‘begin’ and ‘end’ special handlers
  - 4.15.2 Global startup and shutdown handlers.
  - 4.15.3 Action Hook
- 4.16 Functions
  - 4.16.1 Some Useful Functions
- 4.17 Expressions
  - 4.17.1 Constant Expressions
  - 4.17.2 Function Calls
  - 4.17.3 Concatenation
  - 4.17.4 Arithmetic Operations
  - 4.17.5 Bitwise shifts
  - 4.17.6 Relational Expressions
  - 4.17.7 Special Comparisons
  - 4.17.8 Boolean Expressions
  - 4.17.9 Operator Precedence
  - 4.17.10 Type Casting
- 4.18 Variable and Constant Shadowing
- 4.19 Statements
  - 4.19.1 Action Statements
  - 4.19.2 Variable Assignments
  - 4.19.3 The pass statement
  - 4.19.4 The echo statement
- 4.20 Conditional Statements
- 4.21 Loop Statements
- 4.22 Exceptional Conditions
  - 4.22.1 Built-in Exceptions
  - 4.22.2 User-defined Exceptions
  - 4.22.3 Exception Handling
- 4.23 Sender Verification Tests
- 4.24 Modules
  - 4.24.1 Declaring Modules
  - 4.24.2 Scope of Visibility
  - 4.24.3 Require and Import
- 4.25 Dynamically Loaded Modules
  - 4.25.1 Loadable Library
  - 4.25.2 Interface Module
  - 4.25.3 Creating a Mfmod Structure
    - 4.25.3.1 mfmodnew invocation
- 4.26 MFL Preprocessor
  - 4.26.1 Preprocessor Configuration
  - 4.26.2 Preprocessor Usage
  - 4.26.3 Preprocessor Macros
- 4.27 Example of a Filter Script File
- 4.28 Reserved Words
5 The MFL Library Functions
- 5.1 Sendmail Macro Access Functions
- 5.2 tr, dc, and sq functions
- 5.3 The sed function
- 5.4 String Manipulation Functions
- 5.5 String formatting
- 5.6 Character Type
- 5.7 I/O functions
- 5.8 Filtering functions
  - 5.8.1 Filters and Filter Pipes
- 5.9 Email processing functions
- 5.10 Envelope Modification Functions
- 5.11 Header Modification Functions
- 5.12 Body Modification Functions
- 5.13 Message Modification Queue
- 5.14 Mail Header Functions
- 5.15 Mail Body Functions
- 5.16 EOM Functions
- 5.17 Current Message Functions
- 5.18 Mailbox Functions
- 5.19 Message Functions
  - 5.19.1 Header functions
  - 5.19.2 Message body functions
  - 5.19.3 MIME functions
  - 5.19.4 Message digest functions
- 5.20 Quarantine Functions
- 5.21 SMTP Callout Functions
- 5.22 Compatibility Callout Functions
- 5.23 Internet address manipulation functions
- 5.24 DNS Functions
  - 5.24.1 dns_query
  - 5.24.2 Simplified DNS functions
- 5.25 Geolocation functions
- 5.26 Database Functions
- 5.27 Control Database
- 5.28 System functions
- 5.29 System User Database
- 5.30 Sieve Interface
- 5.31 Interfaces to Third-Party Programs
  - 5.31.1 SpamAssassin
  - 5.31.2 ClamAV
- 5.32 Rate limiting functions
- 5.33 Greylisting functions
- 5.34 Special Test Functions
- 5.35 Mail Sending Functions
- 5.36 Blacklisting Functions
- 5.37 SPF Functions
- 5.38 DKIM
  - 5.38.1 Setting up a DKIM record
- 5.39 Sockmap Functions
- 5.40 National Language Support Functions
- 5.41 Syslog Interface
- 5.42 Debugging Functions
- 5.43 Informative Functions
- 5.44 Mfmod Interface Functions
6 Using the GNU Emacs MFL Mode
7 Configuring mailfromd
- 7.1 Special Configuration Data Types
- 7.2 Base Mailfromd Configuration
- 7.3 Preprocessor Configuration
- 7.4 DNS Resolver Configuration
- 7.5 Server Configuration
- 7.6 Milter Connection Configuration
- 7.7 Logging and Debugging configuration
- 7.8 Timeout Configuration
- 7.9 Call-out Configuration
- 7.10 Privilege Configuration
- 7.11 Database Configuration
- 7.12 Runtime Constants Configuration
- 7.13 Standard Mailutils Statements
8 Mailfromd Command Line Syntax
- 8.1 Command Line Options.
- 8.2 Starting and Stopping
9 Using mailfromd with Various MTAs
- 9.1 Using mailfromd with Sendmail.
- 9.2 Using mailfromd with MeTA1.
- 9.3 Using mailfromd with Postfix
10 calloutd
- 10.1 Calloutd Configuration
- 10.2 Calloutd Command-Line Options
- 10.3 The Callout Protocol
11 mfdbtool
- 11.1 Invoking mfdbtool
- 11.2 Configuring mfdbtool
12 mtasim — a testing tool
- 12.1 mtasim interactive mode mode
- 12.2 mtasim expect commands
- 12.3 Trace Files
- 12.4 Daemon Mode
- 12.5 Summary of the mtasim Administrative Commands
- 12.6 mtasim command line options
13 Pmilter multiplexer program.
- 13.1 Pmult Configuration
- 13.2 Pmult Example
- 13.3 Pmult Invocation
14 How to Report a Bug
Appendix A Gacopyz
Appendix B Time and Date Formats
Appendix C Upgrading
- C.1 Upgrading from 8.17 to 9.00
- C.2 Upgrading from 8.16 to 8.17
- C.3 Upgrading from 8.14 to 8.15
- C.4 Upgrading from 8.13 to 8.14
- C.5 Upgrading from 8.7 to 8.8
- C.6 Upgrading from 8.5 to 8.6
- C.7 Upgrading from 8.2 to 8.3 (or 8.4)
- C.8 Upgrading from 7.0 to 8.0
- C.9 Upgrading from 6.0 to 7.0
- C.10 Upgrading from 5.x to 6.0
- C.11 Upgrading from 5.0 to 5.1
- C.12 Upgrading from 4.4 to 5.0
- C.13 Upgrading from 4.3.x to 4.4
- C.14 Upgrading from 4.2 to 4.3.x
- C.15 Upgrading from 4.1 to 4.2
- C.16 Upgrading from 4.0 to 4.1
- C.17 Upgrading from 3.1.x to 4.0
- C.18 Upgrading from 3.0.x to 3.1
- C.19 Upgrading from 2.x to 3.0.x
- C.20 Upgrading from 1.x to 2.x
Appendix D GNU Free Documentation License
- D.1 ADDENDUM: How to use this License for your documents
Concept Index