talkd(1Mtcp)

talkd, otalkd -- remote user communication server

Synopsis

in.talkd

in.otalkd

Description

talkd is the server that notifies a user that somebody else wants to initiate a conversation. It acts as a repository of invitations, responding to requests by clients wishing to rendezvous to hold a conversation.

In normal operation, a talk client initiates a rendezvous by sending a CTL_MSG to the server of type LOOK_UP (see the protocols/talkd.h header file). This causes the server to search its invitation tables to check if an invitation currently exists for the client. If the lookup fails, the caller then sends an ANNOUNCE message. This causes the server to broadcast an announcement on the callee's login ports requesting contact. When the callee responds, the local server first uses the recorded invitation to respond with the appropriate rendezvous address. Then, the caller and callee client programs establish a stream connection through which the conversation takes place.

Usage

otalkd is an older version of talkd. otalkd supports an architecture-dependent version of the talk protocol, whereas talkd supports an architecture-independent version of the talk protocol. Since the two protocols use different UDP ports, it is permissible to configure inetd to run both versions simultaneously (this is the default configuration). When a talk request is received, the user is instructed to run either talk or otalk, depending on which protocol is being used by the remote user.

References

inetd(1Mtcp), services(4tcp), talk(1tcp), write(1)