I apologise if this is posted in the wrong stackexchange but I am currently in the process of building and testing a router running pfSense.
Having recently had a line fault, the BT Openreach engineer that did the repair told me of the huge cost implications of a subscriber causing the fault. As such, I began to question whether or not a router misconfigured with either a software or hardware fault/issue could cause issues on the telecomms network externally. This does seem absurd to be, surely the network should be pretty well protected against router issues and only the subscriber would be knocked offline should an issue arise but I wanted to be absolutely certain.