On 02/11/2016 12:03 AM, Graeme Fowler wrote: > On 9 Feb 2016, at 14:29, Konstantin Boyandin <[email protected]> wrote: >> The above Exim behaviour has happened just few times. Nameservers' >> responses are being monitored 24/7 and they didn't show any quirks. > > With the same granularity that Exim has? Are the resolvers the same in each case?
Every 5 minutes. Affirmative, same resolvers. If I make it significantly more frequent, VM will spend most if its time wasting bandwidth and CPu time on checking DNS records >> Question: does Exim uses /etc/hosts records (as specified in >> /etc/nsswitch.conf ) before trying DNS resolution? Looks like it doesn’t. > > Not for an MX record, no - there’s no way to indicate an MX in /etc/hosts. Actually, after I understood it tries to communicate with A record, I attempted to redirect the A record to correct IP (since domain actual A record isn't ever used from that VM). > It *might* drop back to that for A lookups, depending on the lookup order in /etc/nsswitch.conf. Corresponding entry: hosts: files dns Can the above Exim behaviour be changed? If MX entries fail to resolve, I would rather expect Exim delay the delivery until DNS returns to normal functioning. Sending to A is anyway senseless in many cases. Or, as alternative, add a parameter - host name to fallback if DNS resolution fails. Thanks. Sincerely, Konstantin -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
