pfSense

and the result is "there were errors loading the rules".
1) Maximum state entries this rule can create - (max 0) is allowed, -1, 1.1 and "a" are invalid
(hmmm - why would 0 zero be acceptable to pf? that would be equivalent to specifying "block" for the rule, wouldn't it?)
2) max-src-nodes, max-src-conn, max-src-states, max-src-conn-rate, tcp.established cannot be 0, -1, 1.1, "a" - it has to be a positive integer.
Needs data entry validation to prevent user foot-shooting.
I am happy to do this straight away.