This is the FreeBSD port of the OpenBSD relayd and relayctl.

relayd 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 group.  When availability is con-
firmed, Layer 3 and/or layer 7 forwarding services are set up by relayd.

Layer 3 redirection happens at the packet level; to configure it, relayd
communicates with pf(4).

The following relayd functionality is not (yet) implemented in FreeBSD:
- carp demote
- modifying routing tables
- snmp traps

The relayctl program controls the relayd(8) daemon.