ipsvd is a set of internet protocol service daemons for Unix. It currently includes a TCP/IP service daemon, an SSLv3 TCP/IP service daemon (Linux and MacOSX), and an UDP/IP service daemon.

An internet protocol service (ipsv) daemon waits for incoming connections on a local socket; for new connections, it conditionally runs an arbitrary program with standard input reading from the socket, and standard output writing to the socket (if connected), to handle the connection. Standard error is used for logging.

ipsv daemons can be told to read and follow pre-defined instructions on how to handle incoming connections; based on the client's IP address or hostname, they can run different programs, set a different environment, deny a connection, or set a per host concurrency limit.

Normally the ipsv daemons are run by a supervisor process, such as runsv from the runit package, or supervise from the daemontools package. ipsvd can be used to run services normally run by inetd, xinetd, or tcpserver.