IMAPd - Internet Message Access Protocol server
/usr/etc/imapd
imapd is a server which supports the IMAP4 remote mail access protocol as documented in RFC-1730. imapd is invoked by the internet server (see inetd(8)), normally for requests to connect to the IMAP4 port as indicated by the /etc/services file (see services(5)). Normally, this is port 143.
imapd can also be accessed via rsh(1C) by many Unix-based clients. To do this, the imapd binary must have a link to /etc/rimapd since this is where this software expects it to be located.
rsh(1C) ipopd(8C)