Missing MX, there’s actually syntax accepted by major SMTP servers to disable SMTP for domain:
example.com. MX 0 . Ondrej -- Ondřej Surý — ISC > On 9 Jul 2020, at 16:06, Matthew Richardson <matthe...@itconsult.co.uk> wrote: > > On a related issues there were (perhaps long ago) issues if the A record > for a domain had an SMTP server on it, where email could sometimes be > delivered to that A record rather than the MX. I had (again long ago: > 10-15 years) actually seen this occur. > > Do people think that this problem could still occur these days? What sort > of transient (presumably DNS) failure might cause an SMTP server to deliver > to A rather than MX? > > Best wishes, > Matthew > > ------ >> From: Anand Buddhdev <ana...@ripe.net> >> To: "@lbutlr" <krem...@kreme.com>, bind-users <bind-users@lists.isc.org> >> Cc: >> Date: Thu, 9 Jul 2020 14:43:04 +0200 >> Subject: Re: Dumb Question is an A or AAAA record required? > >>> On 09/07/2020 14:21, @lbutlr wrote: >>> >>> Given a domain that is hosted and used for email and web, is an A >>> record for that domain actually required? >> >> It's not *required*. But see below. >> >>> That is, if bob.tld is hosted by example.com can you simply have >>> >>> NS ns1.example.com >>> NS ns2.example.com >>> MX mx.example.com >>> >>> www CNAME www.example.com >>> >>> Without specifying >>> >>> A 11.22.33.444 >> >> These days, many folk try to reach websites by typing just the bare >> domain name without the "www" prefix. >> >> If a user types "bob.tld" into a browser, the browser will issue an >> address lookup for "bob.tld", causing the resolver to ask for A and AAAA >> records for "bob.tld". If you don't have an A record at the zone apex, >> the browser will not get back any address and display an error message >> for the user. An alert user might try "www.bob.tld" but most users are >> likely to just give up. >> >> So while it's not *required* to have an address record at the apex, it's >> good practice to have one. >> >> Anand >> _______________________________________________ >> Please visit https://lists.isc.org/mailman/listinfo/bind-users to >> unsubscribe from this list >> >> ISC funds the development of this software with paid support subscriptions. >> Contact us at https://www.isc.org/contact/ for more information. >> >> >> bind-users mailing list >> bind-users@lists.isc.org >> https://lists.isc.org/mailman/listinfo/bind-users > > _______________________________________________ > Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe > from this list > > ISC funds the development of this software with paid support subscriptions. > Contact us at https://www.isc.org/contact/ for more information. > > > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information. bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
