I have never worried about port 113 in the grc scans, as well as others like it.
Have many servers out, never had a problem because of port 113 that I am aware of.
A self proclaimed UNIX god, did a port scan on the server and was trying to make it look real bad in front of the owner that this port was open.
I am interested in what others are doing about port 113 or even a link to a FAQ that describes why you should not have it opne.
Thanks in advance.