“From Microsoft
Best practices recommend blocking all TCP/IP ports that are not actually being used, and most firewalls including the Windows Internet Connection Firewall (ICF) block those ports by default. For this reason, most machines attached to the Internet should have RPC over TCP or UDP blocked. RPC over UDP or TCP is not intended to be used in hostile environments such as the Internet. More robust protocols such as RPC over HTTP are provided for hostile environments.”

Does COMODO use RPC over TCP or UDP, does COMODO use RPC over HTTP instead, as it looks like it should?

This is from a post in another part of COMODO forums.

Cheers, rotty

CPF does not use any RPC.
FYI, RPC is for distributed computing which involves many applications communicating with each other.