mod_autohost
For sites that run a large number of <VirtualHost>s for
proftpd, it can be cumbersome to configure them all in
the proftpd.conf file. Adding or removing virtual server
configurations require restarting the daemon, as do changes to one of the
server configurations. The daemon also consumes memory for each server
configuration, and the memory footprint for the daemon process can grow
large for large numbers of servers.
The mod_autohost module allows for server configurations to
be configured in individual files, and for those configuration to be used
in an "on demand" fashion. Rather than loading the configurations into
memory when the daemon starts up, the daemon will check the IP address and
port being contacted by a connecting client, check in the filesystem for
a mod_autohost configuration file for that address/port,
dynamically parse the configuration, and insert the configuration into
the session's process space. Thus changes to the configuration are
seen whenever a client connects, without requiring a daemon restart.
The memory footprint is reduced because proftpd, via
mod_autohost, only reads and uses the needed configuration.
This module is contained in the mod_autohost file for
ProFTPD 1.3.x, and is not compiled by default. Installation
instructions are discussed here.
The most current version of mod_autohost can be found at:
http://www.castaglia.org/proftpd/
Please contact TJ Saunders <tj at castaglia.org> with any questions, concerns, or suggestions regarding this module.
The AutoHostConfig directive specifies the path that
mod_autohost checks for, when handling incoming connections.
The given path must be an absolute path, and may contain the
following variables, which will be interpolated:
mod_autohost
to function.
Examples
With an AutoHostConfig of:
/etc/ftpd/vhosts/%0/autohost.confand a client connecting to 1.2.3.4, the above path would expand into:
/etc/ftpd/vhosts/1.2.3.4/autohost.confGiven a path of:
/etc/ftpd/vhosts/%1/%2/%3/%4/%p/vhost.confand a client connecting to 1.2.3.4, port 2121,
mod_autohost
would check for the following file:
/etc/ftpd/vhosts/1/2/3/4/2121/vhost.conf
The AutoHostEngine directive enables or disables the module's
runtime checks for dynamic server configuration files. If it is set to
off this module does no checking. Use this directive to disable the
module instead of commenting out all mod_autohost directives.
The AutoHostLog directive is used to a specify a log file for
mod_autohost reporting and debugging. The path
parameter must be the full path to the file to use for logging. Note that
this path must not be to a world-writeable directory and, unless
AllowLogSymlinks is explicitly set to on (generally a
bad idea), the path must not be a symbolic link.
The AutoHostPorts directive is used to specify a list of
port numbers on which proftpd should listen. By default,
proftpd listens on a wildcard socket, which means
that a single socket can be used to listen for all address for a given
port. But there is no such thing as a socket which can listen on
all ports. Thus mod_autohost needs to know when to
listen on other ports.
Note that the AutoHostPorts directive is only needed
if your AutoHostConfig path uses the "%p" variable
(i.e. uses the port number to which the client connected as part
of the path to the matching configuration).
For example, if your AutoHostConfig path included configurations
for servers on non-standard ports, you would need to use the
AutoHostPorts directive to list those ports, so that
proftpd could handles connections to them:
<IfModule mod_autohost.c>
AutoHostEngine on
AutoHostLog /etc/ftpd/var/autohost.log
# This is required for mod_autohost to work
AutoHostConfig /etc/ftpd/vhosts/%0/%p/autoconf.conf
# Define the other non-standard ports for which we have config files
AutoHostPorts 2121 2222 4444
</IfModule>
mod_autohost, copy the mod_autohost.c
file into:
proftpd-dir/contrib/after unpacking the latest proftpd-1.3 source code. For including
mod_autohost as a staticly linked module:
./configure --with-modules=mod_autohostAlternatively,
mod_autohost could be built as a DSO module:
./configure --enable-dso --with-shared=mod_autohostThen follow the usual steps:
make make install
Example configuration:
<IfModule mod_autohost.c>
AutoHostEngine on
AutoHostLog /etc/ftpd/var/autohost.log
# This is required for mod_autohost to work
AutoHostConfig /etc/ftpd/vhosts/%0/autoconf.conf
</IfModule>
With this configuration, a client connecting to 1.2.3.4 would cause
mod_autohost to look for the following path:
/etc/ftpd/vhosts/1.2.3.4/autohost.confIf the file is not present,
proftpd handles the connection
as it normally would.
Caveats
The SocketBindTight directive cannot be "on"
if mod_autohost is to work directly. With
SocketBindTight being off by default, proftpd
listens for incoming connections on a wildcard socket, which will
receive connections to all IP addresses on that port.
mod_autohost relies on this behavior. If
SocketBindTight is set to on, then proftpd will
listen only to the addresses of the servers configured in
proftpd.conf, and any autohost.conf files will
be useless.
The DefaultServer directive will have no effect if it appears
in an autohost.conf file.
The mod_tls module will not be able to properly prompt for
passphrases for keys in an autohost.conf file on server startup.
IPv6 addresses are not currently handled by mod_autohost.