[Wolves] Exim sender verify problem

[Wayne]

Adam Sweet wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Wayne wrote:
>
>   
>> That still hasn't solved it, it fact its worse!
>> I now get R=dnslookup defer (-1) host lookup didnot complete
>> and retry timout exceeded
>> VERY quickly and its bounced back to me.
>>
>> I wonder whether its because although the domain pings to 85.92.73.96,
>> the email server listed in the MX
>> record is at 195.74.102.146 and has no reverse dns?
>>     
>
> Can you paste in the actual output from Exim's logs. I can't follow
> what's happening.
>
>   
Incoming mail (via my no-ip backup server)
2007-10-07 04:53:12 H=mail1.no-ip.com [204.16.252.100] sender verify 
defer for <ghowells at remail-ltd.co.uk>: host lookup did not complete
2007-10-07 04:53:12 H=mail1.no-ip.com [204.16.252.100] 
F=<ghowells at remail-ltd.co.uk> temporarily rejected RCPT 
<wayne at machx.co.uk>: Could not complete sender verify

Out:
2007-10-09 16:33:00 1IfH4o-0000pe-Mr <= wayne at machx.co.uk 
H=toshlap.machx.co.uk [192.168.1.4] P=esmtp S=1162 
id=470B9EC6.3070108 at machx.co.uk
2007-10-09 16:33:01 1IfH4o-0000pe-Mr == ghowells at remail-ltd.co.uk 
R=dnslookup defer (-1): host lookup did not complete
2007-10-09 16:33:01 1IfH4o-0000pe-Mr ** ghowells at remail-ltd.co.uk: retry 
timeout exceeded



> Pinging is of no use to you, a lot of people block pings, what you are
> getting out of it though is DNS resolution of hostname to IP address.
> Try telnetting the mail server on the other end on port 25 though the
> fact that you can send mail to it from yahoo says that it's accepting mail.
>
> - From here a lookup on the MX record says:
>
> adam at elmo:~$ dig remail-ltd.co.uk mx
>
> <snip>
>
> ;; ANSWER SECTION:
> remail-ltd.co.uk.       14186   IN      MX      0 remail-ltd.co.uk.
>
> <snip>
>
> ;; ADDITIONAL SECTION:
> remail-ltd.co.uk.       14186   IN      A       85.92.73.96
>
> A forward lookup on remail-ltd.co.uk is as shown above. A reverse lookup
>  on this IP address gives:
>
> adam at elmo:~$ dig -x 85.92.73.96
>
> <snip>
>
> ;; ANSWER SECTION:
> 96.73.92.85.in-addr.arpa. 3054  IN      PTR
> server4.discountdomainsuk.com.
>   

I get this as a dig:

[root at www ~]# dig remail-ltd.co.uk MX

; <<>> DiG 9.3.4-P1 <<>> remail-ltd.co.uk MX
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 42735
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;remail-ltd.co.uk.              IN      MX

;; Query time: 166 msec
;; SERVER: 195.74.102.146#53(195.74.102.146)
;; WHEN: Wed Oct 10 12:05:09 2007
;; MSG SIZE  rcvd: 34


See the 195 addy that you asked about below


> All of which looks pretty above board to me, apart from the fact that
> some people will refuse your mail if you forward lookup and reverse
> lookup don't match, but I guess this a problem with shared servers.
>
> However I've no idea where you're getting 195.74.102.146 from. Which is
> interesting because we have an IP range at work which is almost
> identical to the range this address is in and I happen to know that that
> range belongs to Enta, an ISP in Telford. And they broke our reverse DNS
> and I've been hammering them all day about it, though a quick check
> shows they've fixed mine now.
> In fact, this IP resolves to dns-cache1.enta.net so it may be that they
>   
> fixed my DNS and broke yours :) Are you on Enta? If so it looks like
> they have broken your DNS.
>
>   
Yes I use Enta!

> Try the same commands yourself on your mail server to make sure your
> output makes sense and the results are consistent with each other and
> with mine. I'm using my dad's Plus.net DNS at the mo. You can also
> compare against the output you get from using OpenDNS as below and take
> a look at http://www.dnsstuff.com/ too.
>
> If your DNS is indeed b0rked, you could try using OpenDNS for a while:
>
> http://www.opendns.com/
>
> they're DNS servers are listed at the bottom.
>
>   
I swopped DNS to the ones you said and I get a proper dig now!
And mail goes! Yeha.

Bloody Enta, first thing I did was ring them and they told me everything 
was fine at ENTA end!

> Other than all this, you could try:
>
> exim -qff
>
> which will force Exim to attempt delivery of everything in your mail
> queue, which you can watch in a different terminal by doing
>
> tail -f /var/log/exim/main.log
>
> or whatever your Exim log file is. The output should point you at the
> fact that the reverse DNS lookup is failing when receiving from them and
> so you are sending them a temporary local error and when you are
> attempting to send to them, you're sending to the wrong place.
>
> ...Or some of other concoction of DNS weirdness which is happening at
> your end.
>
> Regards,
>
> Adam Sweet - DNS Inspector :)
>
> - --
>   

Ta Adam!