Paul Roberts <p...@callevanetworks.com> wrote: > After doing some more packet captures, it looks like a lot of the > queries are related to Sophos live protection DNS lookups (lots of > queries for sophosxl.net), so there are a lot of queries which don't get > resolved.
Good grief. There are a few things you might do to mitigate this idiocy: 0. Block sophosxl.net. Your colleagues responsible for AV might not appreciate this :-) 1. In BIND 9.11+ there are options `fetches-per-zone` and `fetches-per-server` for helping a resolver to cope with overloaded authoritative servers. When you are forwarding you'll have to rely on fetches-per-zone since fetches-per-server will throttle everything. I don't know how fetches-per-zone discovers zone cuts or how well that works in the forwarding case when your resolver is relying on an upstream to do the iteration. 2. Set up sacrificial forwarding IP addresses. These can be additional addresses on your existing forwarders. Configure your resolvers to forward queries for sophosxl.net to the sacrificial addresses instead of the usual ones. Then BIND's address database entries used by most queries won't get polluted by the non-responding servers. You might profitably combine 1. and 2. to make the resolver eagerly drop queries to the sacrificial forwarders. Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ the quest for freedom and justice can never end _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users