Re: [exim] DNS problems with sending via multiple smarthosts

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Author: David Purton
Date:  
To: exim-users
Subject: Re: [exim] DNS problems with sending via multiple smarthosts
Thanks for your help. I've been away for a few days and not able to test
things. Here's the results of what you ask:

On Fri, Jul 19, 2019 at 01:08:28AM +0300, Evgeniy Berdnikov via Exim-users wrote:

[SNIP]

> Quite puzzling... The only difference I see here is the presence of one
> authority record in dns query from Exim, marked as [1au].
> Tcpdump man page states:
>
>        A few anomalies are checked and may result in extra fields enclosed  in
>        square  brackets:   If a query contains an answer, authority records or
>        additional records section, ancount, nscount, or arcount are printed as
>        `[na]', `[nn]' or  `[nau]' where n is the appropriate count.

>
> Running tcpdump with -vvv shows that there is an authority record for root.
> I don't know is this behaviour legal or not, and why this record is present
> in exim queries. But I propose to try two other methods to resolve name:
>
> 1: exim4 -be '${lookup dnsdb{a=smtp.gmail.com}{$value}fail}'


This returns:

    Failed: "lookup" failed and "fail" requested


> 2: perl -e '($n,$a,$t,$l,@ip)=gethostbyname("smtp.gmail.com"); print "n=$n\na=$a\n"; for (@ip) {($w,$x,$y,$z)=unpack('W4',$_); print "$w.$x.$y.$z\n"}'


This returns:

    n=gmail-smtp-msa.l.google.com
    a=smtp.gmail.com
    74.125.68.108


--
David Purton
e: dcpurton@???
m: 0413 626 862