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andrewprouse

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mail to one specific domain returns : " #5.5.0 smtp;550-Verification failed "

I have a problem sending mail from a customer's domain back to mine.

Customer's domain = epmcevilly.co.uk (BT as service provider, ClaraNet as domain host)
My domain = converged-solutions.com (BT as service provider, 1and1 as domain host (unfortunately))

Mail from EPMcEvilly destined for converged-solutions.com is bouncing back with the following message:-


The following recipient(s) could not be reached:

  andrewrouse@converged-solutions.com on 04/05/2006 13:20
  There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
  <convergerged-solutions.com #5.5.0 smtp;550-Verification failed for <PeterJefferies@epmcevilly.co.uk>>


I have looked at similar posts but cant resolve this one. I'm a relative novice at this. I'm using SBS2003 and Exchange at both sites.  My firewall is a SonicWallTZ170 and EPMcEvilly have a BT Voyager2110.  The client can mail everyone but converged-solutions.com (me).

Have tried multiple SMTP servers and combinations of DNS servers with no joy (some different error messages but no success).

Bit confused and unsure of how to check 'mx' records and 'reverse DNS' entries.

I have set the question as 500pts simply because the client is jumping all over me to get this sorted.

Any help would be much appreciated...Thank you

Andy Rouse.
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amaheshwari
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andrewprouse

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thank you but i've already looked through that article and tried to follow it. after a bit of confiusion with the DNS part i think all my DNS records are in place.  The chap in that artice solves it my finding out his firewall won;t accept mail without a vaild 'from' address. I dont think this applies to me or if it does i'm not sure how to check.
Lets break this down:

1. Is this the only domain you are having problems with?
2. use Nslookup to verify thier mx ip
  nslookup <enter>
  set type=mx <enter>
  remote domain

this should return thier MX record
3. attempt to telent to port 25 to that ip  
  IP 25

1.
yes, converged-solutions.com is the ONLY problematic domain


2.
Microsoft Windows [Version 5.2.3790]
(C) Copyright 1985-2003 Microsoft Corp.

C:\Documents and Settings\csl>nslookup
Default Server:  voyager2110.epmcevilly.local
Address:  10.1.1.2

> set type=mx
> converged-solutions.com
Server:  voyager2110.epmcevilly.local
Address:  10.1.1.2

Non-authoritative answer:
converged-solutions.com MX preference = 10, mail exchanger = mx01.1and1.co.uk
converged-solutions.com MX preference = 10, mail exchanger = mx00.1and1.co.uk

converged-solutions.com nameserver = ns33.1and1.co.uk
converged-solutions.com nameserver = ns34.1and1.co.uk
mx01.1and1.co.uk        internet address = 212.227.15.186
mx01.1and1.co.uk        internet address = 212.227.15.134
mx01.1and1.co.uk        internet address = 212.227.15.150
mx01.1and1.co.uk        internet address = 212.227.15.169
mx00.1and1.co.uk        internet address = 212.227.15.134
mx00.1and1.co.uk        internet address = 212.227.15.150
mx00.1and1.co.uk        internet address = 212.227.15.169
mx00.1and1.co.uk        internet address = 212.227.15.186
ns33.1and1.co.uk        internet address = 195.20.224.152
ns34.1and1.co.uk        internet address = 212.227.123.27
>


3.
AH, think we've got something here.

Telnet on port 25 result =
421 mails from 81.155.102.217 refused: Dynamic/Residential IP range listed by NJ
ABL dynablock - http://njabl.org/dynablock.html


Connection to host lost.


Well we've established that its blocked for some reason, any ideas how to proceed from here?
cheers.
Its hard to say,

I would contact them and work with them on the issue

check black lists etc.....
Do you have a reverse dns record ?
could be a routing thing -- try trace route to thier server?

TraceRoute from epmcevilly.co.uk domain to mx00.1and1.co.uk result =

Analysis:
Number of hops: 9
Last hop responding to ICMP: 8, UDP: 8, TCP: 9.
There appears to be a firewall at 212.227.15.186 (hop 9) that blocks ICMP (ping) packets.
The destination appears to block unwanted UDP packets.

Do i have a reverse DNS record ? I'm not sure...let me check dnsstuff.com...
Answer: No PTR records exist for 82.165.54.166. [Neg TTL=86400 seconds]

Ah, so i haven;t got reverse DNS setup. Am i right in thinking the mail could be bouncing due to that alone?

I am going to get onto 1and1 and see what they say about the port 25 block and the lack of Reverse DNS.
http://www.dnsreport.com/tools/dnsreport.ch?domain=converged-solutions.com

converged-solutions.com holds Duplicate MX record, this is a probable issue

Thanks,
some companies will not allow messages if it can do perform a reverse lookup due to the fact it could be spam
you can have multiple MX records note that have diffrent names but point to the same address could be a load balance
phoned 1and1 who weren't at all helpful.  Have had to mail their support department which could take a day or two.

ksharma4 - i have taken the report u found and have forewarded it to 1and1, am awaiting their reply.

Looks like i've got to sit tight and await their reply.  If anyone knows of a quickfix / workround i would be very interested (failing that the complete resolution would be nice)..

cheers guys
yeah host your own dns hehe
i contacted 1and1 and explained in explecit detail my problems and what i deemed to be the solution.  The reply i got was:

" please visit our FAQ page " and " if you enter any error codes into Goolge then follow the link to Microsoft you should be able to resolve any issues ".

...not what i call Customer Service !!

Can anyone reccommend a *good* alternate ISP to host mail (100usrs) and a Web Page ?
SORTED !!!!

BT had a block on the epmcevilly.co.uk domain name which was stopping me using their SMTP server, for some reason only BT can route through to converged-solutions.com, ClaraNet's SMTP & DNS kept dropping mail to converged-solutions.com .

Anyhow, thank you for all your help.
Great to listen that now everything is fine.
who is BT?
British Telecom
glad  you had got it resolved.
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CetusMOD
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