---
name: "Mail::MIMEDefang"
section: "3"
platform: "linux"
package: "mimedefang"
version: "3.6-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Mail::MIMEDefang"
---

# Mail::MIMEDefang(3)

email filtering milter

## NAME

Mail::MIMEDefang - email filtering milter

## DESCRIPTION

Mail::MIMEDefang is a framework for filtering e-mail. It uses Sendmail's "Milter" API, some C glue code, and some Perl code to let you write high-performance mail filters in Perl.

People use MIMEDefang to:

```
    Block viruses
    Block or tag spam
    Remove HTML mail parts
    Add boilerplate disclaimers to outgoing mail
    Remove or alter attachments
    Replace attachments with URL's
    Implement sophisticated access controls.
```

You're limited only by your imagination. If you can think of it and code it in Perl, you can do it with MIMEDefang.

## METHODS

- init\_globals

  Initialize global variables used across MIMEDefang instance and filter.

- print\_and\_flush(text)

  Prints to stdout and flush buffer.

- md\_openlog(tag, facility)

  Initialize e syslog object using Sys::Syslog or Unix::Syslog as appropriate.

- md\_syslog(facility, msg)

  Prints a message to [**syslog**(3)](/syslog/3.md) using the specified facility

- md\_graphdefang\_log

  This is called to log events that occur during mimedefang processing. It should be called from mimedefang-filter with appropriate event names and values.

  Possible examples:

  `"md_graphdefang_log('virus',$VirusName,$filename);"`

  `"md_graphdefang_log('spam',$hits);"`

  `"md_graphdefang_log('bad_filename',$filename,$extension);"`

  If you need to log UTF-8 strings you can call the sub as:

  `"md_graphdefang_log('spam',$hits, undef, 1);"`

- detect\_and\_load\_perl\_modules

  Automatically detect and load Perl modules needed for some features like SpamAssassin, rbl checks, zip file listing and HTML parsing.

- detect\_antivirus\_support

  Check if antivirus support should be loaded by looking at `%Features`

- init\_status\_tag

  Open the status file descriptor

- set\_status\_tag(depth, tag)

  Sets the status tag for this worker inside the multiplexor.

- push\_status\_tag(tag)

  Updates status tag inside multiplexor and pushes onto stack.

- pop\_status\_tag

  Pops previous status of stack and sets tag in multiplexor.

- percent\_encode(str)

  Encode a string with unsafe chars as "%XY" where X and Y are hex digits.

- percent\_encode\_for\_graphdefang(str)

  Encode a string with unsafe chars as "%XY" where X and Y are hex digits.

  Quotes or spaces are not encoded but commas are encoded.

- percent\_decode(str)

  Decode a string previously encoded by **percent\_encode()**.

- write\_result\_line ( $cmd, @args )

  Writes a result line to the RESULTS file.

  `$cmd` should be a one-letter command for the RESULTS file

  `@args` are the arguments for `$cmd`, if any.  They will be **percent\_encode()**'ed before being written to the file.

  Returns 0 or 1 and an optional warning message.

- signal\_unchanged

  Tells mimedefang C program message has not been altered.

- signal\_changed

  Tells mimedefang C program message has been altered.

- in\_message\_context(name)

  Returns 1 if we are processing a message; 0 otherwise.

- in\_filter\_wrapup(name)

  Returns 1 if we are not in filter wrapup; 0 otherwise.

- in\_filter\_context

  Returns 1 if we are inside filter or filter\_multipart, 0 otherwise.

- in\_filter\_end(name)

  Returns 1 if we are inside filter\_end 0 otherwise.

- send\_quarantine\_notifications

  Sends quarantine notification message, if anything was quarantined.

- signal\_complete

  Tells mimedefang C program Perl filter has finished successfully.

  Also mails any quarantine notifications and sender notifications.

- send\_mail(fromAddr, fromFull, recipient, body, deliverymode)

  Sends a mail message using Sendmail.

  Invokes Sendmail without involving the shell, so that shell metacharacters won't cause security problems.

  Delivery mode parameter is the optional sendmail delivery mode arg (default "-odd").

- send\_multipart\_mail(fromAddr, fromName, recipient, subject, body\_text, body\_html, extra\_headers)

  Sends a multipart mail message using Sendmail.

  Invokes Sendmail without involving the shell, so that shell metacharacters won't cause security problems.

- send\_admin\_mail(subject, body)

  Sends a mail message to the administrator

- **read\_commands\_file()**

  This function should only be called from `"filter_sender"` and `"filter_recipient"`. This will read the `"COMMANDS"` file (as described in [**mimedefang-protocol**(7)](/mimedefang-protocol/7.md)), and will fill or update the following global variables: `$Sender`, `@Recipients`, `%RecipientMailers`, `$RelayAddr`, `$RealRelayAddr`, `$RelayHostname`, `$RealRelayHostname`, `$QueueID`, `$Helo`, `%SendmailMacros`.

  If you do not call `"read_commands_file"`, then the only information available in `"filter_sender"` and `"filter_recipient"` is that which is passed as an argument to the function.

### SEE ALSO

[**Mail::MIMEDefang::Actions**(3)](/Mail::MIMEDefang::Actions/3.md)

[**Mail::MIMEDefang::Antispam**(3)](/Mail::MIMEDefang::Antispam/3.md)

[**Mail::MIMEDefang::Antivirus**(3)](/Mail::MIMEDefang::Antivirus/3.md)

[**Mail::MIMEDefang::DKIM**(3)](/Mail::MIMEDefang::DKIM/3.md)

[**Mail::MIMEDefang::DKIM::ARC**(3)](/Mail::MIMEDefang::DKIM::ARC/3.md)

[**Mail::MIMEDefang::Authres**(3)](/Mail::MIMEDefang::Authres/3.md)

[**Mail::MIMEDefang::Mail**(3)](/Mail::MIMEDefang::Mail/3.md)

[**Mail::MIMEDefang::MIME**(3)](/Mail::MIMEDefang::MIME/3.md)

[**Mail::MIMEDefang::Net**(3)](/Mail::MIMEDefang::Net/3.md)

[**Mail::MIMEDefang::RFC2822**(3)](/Mail::MIMEDefang::RFC2822/3.md)

[**Mail::MIMEDefang::Unit**(3)](/Mail::MIMEDefang::Unit/3.md)

[**Mail::MIMEDefang::Utils**(3)](/Mail::MIMEDefang::Utils/3.md)