xinetd

replacement for inetd with many enhancements

xinetd has access control mechanisms, extensive logging capabilities, the ability to make services available based on time, and can place limits on the number of servers that can be started, among other things. It has the ability to redirect TCP streams to a remote host and port. This is useful for those of that use IP masquerading, or NAT, and want to be able to reach your internal hosts. It also has the ability to bind specific services to specific interfaces. This is useful when you want to make services available for your internal network, but not the rest of the world. Or to have a different service running on the same port, but different interfaces.