is a daemon to relay and dynamically redirect incoming connections to
a target host.
Its main purposes are to run as a load-balancer, application layer
gateway, or transparent proxy.
The daemon is able to monitor groups of hosts for availability, which
is determined by checking for a specific service common to a host
When availability is confirmed,
layer 3 and/or layer 7 forwarding services are set up by
Layer 3 redirection happens at the packet level; to configure
to properly set up
rules, the following line is required in the filter section of
Layer 7 relaying happens at the application level and is
Various application level filtering and protocol-specific
load-balancing options are available for relays.
works in terms of the following
relays, protocols, redirections, and tables.
represents a layer 7 load-balancing instance.
Each instance translates to a listening TCP or UDP port.
defines which actions, if any, are taken on the
packet payload as data crosses a relay.
represents a layer 3 load-balancing instance.
Each instance translates to a
rdr-to rule being added.
represents a group of hosts which can be checked for
availability using the same method.
Each table contains at least one host.
If a table is used in a layer 3 load-balancing instance, it
will be mapped to a
table containing only those hosts which are up.
All these entities can be configured in
can be used to alter or report on the status of each entity.
The options are as follows:
|-D macro = value
to be set to
on the command line.
Overrides the definition of
in the configuration file.
Do not daemonize.
If this option is specified,
will run in the foreground and log to
Specify an alternative configuration file.
The default is
Only check the configuration file for validity.
Produce more verbose output.