Szerző: Konstantin Boyandin Dátum: Címzett: exim-users Tárgy: Re: [exim] Exim trying to send email to A record of recipient domain
On 02/09/2016 01:52 PM, Evgeniy Berdnikov wrote: > On Tue, Feb 09, 2016 at 11:20:37AM +0600, Konstantin Boyandin wrote:
>> The funny thing is Exim attempt to connect to A record address (in
>> this example, 10.1.2.3) of the target domain (example.net in this
>> case), whereas its MX records (10.10.1.2, 10.20.2.3, for the sake of
>> example) are valid, accessible and accept mail normally.
>
> MX records must contain names, resolvable to ip addresses.
They do. I also checked that
- all the nameservers return the same MX record
- all the nameservers resolve MX record FQDN to the same IP address
(different from A record for the domain)
>> I tried to use /etc/hosts and add corresponding line, like
>>
>> 10.10.1.2 example.net
>>
>> (the IP is the IP of MX record for the domain), but Exim ignores
>> that and still does actual DNS requests for A record and attempts to
>> use it.
>>
>> Can this Exim behavior be changed? At least, force Exim to consult
>> /etc/hosts in such a case,
>
> Just modify DNS zone to make your custom DNS replies.
Domain DNS zone is valid and no MX record points to the same address
that is assigned for A record. Why should I modify it?
>> if DNS requests time out (the only cause
>> of this behavior that I can offer).
>
> This should not be the case, IMHO. Run any network traffic analyzer
> to study contents of DNS requests and answers.
The above Exim behaviour has happened just few times. Nameservers'
responses are being monitored 24/7 and they didn't show any quirks.
Question: does Exim uses /etc/hosts records (as specified in
/etc/nsswitch.conf ) before trying DNS resolution? Looks like it doesn't.
