oidentd
Configurable ident daemon with IP masquerading support
oidentd is an RFC 1413 compliant ident daemon that runs on Linux, FreeBSD, OpenBSD, NetBSD, DragonFly BSD, and some versions of Darwin and Solaris. oidentd can handle IP/NAT masqueraded connections on many operating system kernels. oidentd has a flexible mechanism for specifying ident responses. Users can be granted permission to specify their own responses, and different responses can be sent depending on host and port pairs.