ProFTPD module mod_dynmasq

The mod_dynmasq module is designed for those sites that use the MasqueradeAddress directive in conjunction with DNS names whose addresses periodically change, e.g. "dyndns" addresses. The proftpd daemon is not aware of any changes to the IP address for a MasqueradeAddress that happen after the daemon has started up. The mod_dynmasq module periodically checks all configured MasqueradeAddress directives and resolves their IP addresses, updating the stored addresses as needed.

This module is contained in the mod_dynmasq.c file for ProFTPD 1.2.10 and later, and is not compiled by default. Installation instructions are discussed here.

The most current version of mod_dynmasq is distributed with the proftpd source distribution.


Please contact TJ Saunders <tj at> with any questions, concerns, or suggestions regarding this module.



Syntax: DynMasqRefresh secs
Default: None
Context: "server config"
Module: mod_dynmasq
Compatibility: 1.2.10

The DynMasqRefresh directive configures the amount of time, in seconds, between mod_dynmasq's checking and updating of all MasqueradeAddress directives. If no DynMasqRefresh directive is configured, then the module will do no checking.

The process of resolving a DNS name to its IP address can, depending on the DNS configuration, take a noticeable amount of time. This, combined with the number of MasqueradeAddress directives in your proftpd.conf, can cause mod_dynmasq to make the daemon unavailable while it resolves all addresses. Therefore it is highly recommended that the configured interval be as long as possible, for example for 8 hours.


  <IfModule mod_dynmasq.c>
    # Refresh any configured MasqueradeAddress directives every 8 hours
    DynMasqRefresh 28800

See also:


To install the mod_dynmasq module, follow the usual steps for using third-party modules in proftpd:
  ./configure --with-modules=mod_dynmasq
To build mod_dynmasq as a DSO module:
  ./configure --enable-dso --with-shared=mod_dynmasq
Then follow the usual steps:
  make install

For those with an existing ProFTPD installation, you can use the prxs tool to add mod_dynmasq, as a DSO module, to your existing server:

  # prxs -c -i -d mod_dynmasq.c

Author: $Author: castaglia $
Last Updated: $Date: 2013/08/14 21:40:17 $

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