To make a Unix system available as a server for GAP you must (1) install GAP3d on /usr/local/lib/courier, (2) run xnscourierd from /etc/rc.local or wherever, (3) run (once) the program ../examples/ch/registerhost to register this host in the clearinghouse. We have tested GAP3d with XDE NSChat, with Star, and with Interlisp CHAT. It seems to work adequately. However, under heavy usage it occasionally hangs; we're working on it. We have tested gaptelnet with GAP3d, with Services-8 remote system administration, and with Services-8 ITS. It is rumored not to work with Interlisp-D remote system administration or with XDE REXEC service. There is also an untested GAP version2 server available as GAP2d.