moderated Re: incorrect bounces #bug


On Sat, Oct 10, 2020 at 8:25 AM Phil Karn <karn@...> wrote:

I've had my email feeds cut off several times recently because incorrectly concluded that my email was bouncing. My domain name ( has MX records pointing at gmail's mail servers along with an A (IPv4) address record pointing at my web server. What's happening is that occasionally fails to resolve the MX records and attempts to deliver email to the SMTP server on my web hosting site, which isn't set up to handle it.

After a bunch of research, it appears that the DNS resolver on our main email server was failing under high load in a way that I was not aware of. Most of the time this was mitigated by us retrying the DNS lookup, but for some cases, like yours, it would cause an error. With the extra DNS cache capacity I added earlier this week along with some tweaks to our lookup code, it looks like we haven't had any failures lately and email to you is flowing ok.


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