Here's what I'm showing: protection.outlook.com. 7200 IN NS ns1-gtm.glbdns.o365filtering.com. protection.outlook.com. 7200 IN NS ns2-gtm.glbdns.o365filtering.com.
Not bad at all. Honestly, the amount of traffic for each person is probably minimal, and I would think it would affect those DNS servers before ours. I was more thinking that most DNS resolvers will cache for some period of time and repeated lookups within the TTL would probably start rate limiting for most. Sincerely, Eric Tykwinski TrueNet, Inc. P: 610-429-8300 -----Original Message----- From: mailop [mailto:[email protected]] On Behalf Of Tim Bray Sent: Friday, November 11, 2016 12:42 PM To: [email protected] Subject: Re: [mailop] Office365 question... On 11/11/16 03:15, Bill Cole wrote: > > I think it's a perfectly reasonable TTL for a mail system that uses > round-robin DNS for loadbalancing and high availability. Arbitrarily > forcing it higher on the client end could have unintended negative > consequences. (quick reply) The other question is, what is the TTL for the NS records for the same domain. If the NS has a long TTL, then looking up the A record is pretty cheap (one DNS lookup to authoritative server). If the NS has short TTL, then looking up the A record is pretty expensive (potentially all the way back to the root again). NS records look like short TTL to me. And generally short TTLs all the way, although I've not had a proper dig to see. Tim _______________________________________________ mailop mailing list [email protected] https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
