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Problem sending emails to a particular domain name

Hello,

Here is my problem : i have set up an exchange 2007 platform. My hub transport server is configured to use DNS to send emails directly through the Internet. For the moment, it works for every domain except one.

When I try to send emails to this exception, in the queue viewer I have an error message returned : "451 4.4.0 DNS Query failed".

But when I open a command prompt on my hub transport server, I type these lines :
nslookup
server my_dns_server
set type = MX
domain_name_causing_problems

The name resolution is done successfully...

Does anyone have an idea that could help me ?

Thanks in advance.

hodgeyohn

i have seen dns have issues.
try changing exchange to use dns servers 4.2.2.2, and 4.2.2.3. test it then.

Xyptilon2

Flush the cache and retry?

xelablub

ASKER

HI,

I tried with the public DNS server 4.2.2.2: same error.

I flushed the DNS cache: same error.

I added a new send connector with a weight of 1 for the domain causing problem. This connector sends emails directly to the IP (to be sure there is no dns resolution): same error.......

Good night.

Xyptilon2

I found this: (which may be relevant to you:) http://technet.microsoft.com/en-us/library/bb851512.aspx

Have you tried forwarding DNS queries to an external DNS server and retry sending the message?

ASKER CERTIFIED SOLUTION

xelablub

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Xyptilon2

I believe that is what i suggested, forwarding queries to an external DNS server, anyway, glad to see that it is working, perhaps your DNS cache is corrupt, it happens all the time :)

xelablub

ASKER

The thing is that it was already sending emails through an external DNS. But my exchange server was using only the internal settings (my internal DNS server was relaying emails to an external DNS afterwards). The thing is that my external DNS settings also point to my internal DNS server !

Anyway, if I was not using an external DNS at all, no emails could be sent, don't you think ? But my issue concerned only one domain. All others were working fine.