I keep getting hack attemps on port: 111 using portsentry any one know what this port is or used for?

http://www.sans.org/newlook/resources/IDFAQ/blocking.htm

Check this link out.

You can get a list of common port here:

http://www.networkice.com/advice/Exploits/Ports/default.htm

If you want to see specifically what you are running take a look at the file:

/etc/services

Which on my RaQ lists 111 as:

sunrpc 111/tcp
sunrpc 111/tcp portmapper sunrpc 111/udp
sunrpc 111/udp portmapper

allan