--On Monday, October 05, 2015 10:46 AM -0400 "James B. Byrne" <byrnejb at harte-lyne.ca> wrote: > So, is there any convenient way to construct an IPTables rule to block > all IPs associated with a given Domain Name server? Doing DNS queries within the kernel netfilter path would be bad. You could run a cron job to update an iptables chain periodically with the results of a dig query. Some Perl could be used to do the query and generate the iptables commands.