-\fBPredefChannelsOnly\fR (boolean)
-If enabled, no new channels can be created. Useful if you do not want to have
-other channels than those defined in [Channel] sections in the configuration
-file on this server.
+\fBPAMIsOptional\fR (boolean)
+When PAM is enabled, all clients are required to be authenticated using PAM;
+connecting to the server without successful PAM authentication isn't possible.
+If this option is set, clients not sending a password are still allowed to
+connect: they won't become "identified" and keep the "~" character prepended
+to their supplied user name.
+Please note:
+To make some use of this behavior, it most probably isn't useful to enable
+"Ident", "PAM" and "PAMIsOptional" at the same time, because you wouldn't be
+able to distinguish between Ident'ified and PAM-authenticated users: both
+don't have a "~" character prepended to their respective user names!