oidentd

Configurable IDENT Server That Supports NAT/IP Masquerading

Oidentd is an ident (rfc1413 compliant) daemon that runs on Linux, Darwin, FreeBSD, OpenBSD, NetBSD, and Solaris. oidentd can handle IP masqueraded/NAT connections on Linux, Darwin, FreeBSD (ipf only), OpenBSD, and NetBSD. Oidentd has a flexible mechanism for specifying ident responses. Users can be granted permission to specify their own ident responses. Responses can be specified according to host and port pairs.