About oidentd

Flexible, RFC 1413 compliant Ident daemon with NAT support.

oidentd is a flexible, RFC 1413 compliant Ident server. It runs on Linux, FreeBSD, OpenBSD, NetBSD, and DragonFly BSD. It is highly configurable, allowing the system administrator to define custom responses based on host and port pairs. The administrator can also grant capabilities to individual users to allow them to change their Ident replies, generate random replies, or hide their connections. oidentd supports lookups for NAT connections and is able to forward queries to other servers.

oidentd was originally written by Ryan McCabe in 1998. Since January 2018, it is maintained by Janik Rabe, with contributions from several other volunteers.

The Ident Protocol is used primarily on IRC to detect and prevent abuse and to identify users connecting through shared networks.


  • oidentd is highly configurable, but configuration is optional and sensible defaults are provided.
  • oidentd provides system administrators with a granular, capability-based access control system.
  • Conditional replies enable users to send replies based on connection information, such as ports and IP addresses.
  • oidentd is capable of sending hidden, randomized, and spoofed replies.
  • oidentd can optionally handle requests for NAT connections and is capable of forwarding requests to other Ident servers.
  • Both IPv4 and IPv6 are supported.
  • oidentd is free software licensed under the GNU GPLv2.