Open recursive resolver

First a question - you say the site lost internet access - is this from the site (outbound) or to the site (inbound)? Most of my client sites run their own DNS servers (usually Windows AD) and outbound internet access does not require any service rules (inbound or outbound) to be configured on the router/firewall - the NAT process handles everything transparently. It looks to me as if those services may have been configured by someone who perhaps was following instructions without knowing what they were about.