mail to a specific domain bouncing back

Posted on 2011-05-09
Last Modified: 2012-06-27
We have a single sbs2008 running exchange.

Everything is working fine, apart from mail to a particular domain bounces back. The reported error is as follows :-

The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.

I have tried it from an external scource and the mail gets through OK. I presume there is a problem locally, but as all other mail is getting through to the other destinations, I am unsure where to start.

I have also check that our IP address is not on any black lists, and we are not.

The NDR mesage seems to indicate that the mail address is not valid at the destination, but we know that it is.

The message bounces back almost straight away, so again that lead me to believe that it was not leaving our domain.

Can anyone assist in tracking this problem down?

Many thanks.
Question by:nigelbeatson
    LVL 22

    Expert Comment

    by:Matt V
    Enable message tracking and ensure that your Exchange server is contacting the correct mail server for the domain.  There may be a DNS lookup issue with the MX record on your side.
    LVL 56

    Expert Comment

    by:Cliff Galiher
    The behavior you describe is common when the destination has implemented a spam technique called "greylisting." I would contact the destination and see if they can assist in troubleshooting.

    LVL 2

    Expert Comment

    I have found that Outlook sometimes has corrupted entries in it's Globals cache.  Try opening a new message, start to type the email address in and then delete the Autofil that comes up.  Close that message, open a new one, and try manually typing in the email address.
    LVL 5

    Expert Comment

    Read the bounceback from the bottom upwards.  Is the message being generated by the recipient exchange server?  Are you sure the message is even getting there.

    Perform an MX lookup on your SBS and check if it can find the MX record for the recipient domain.  Compare that against

    Author Comment

    Thankyo for your assistance, and may I apologise for taking so long to respond.

    With regards to greylisting, could this be at the domain level, as I can send mail to this address from anywhere else apart from within our own network. All other mail is getting through to recipients.

    MXLOOKUP seams to find our server OK.

    Here is the NDR :-

    Diagnostic information for administrators:
    Generating server: SBS2008.tgbdom.local
    #550 5.1.1 RESOLVER.ADR.RecipNotFound; not found ##
    Original message headers:
    Received: from SBS2008.tgbdom.local ([fe80::415b:f737:c0e7:3927]) by
     SBS2008.tgbdom.local ([fe80::415b:f737:c0e7:3927%10]) with mapi; Tue, 24 May
     2011 11:35:06 +0100
    Content-Type: application/ms-tnef; name="winmail.dat"
    Content-Transfer-Encoding: binary
    From: carol higgins <>
    To: "" <>
    Date: Tue, 24 May 2011 11:35:04 +0100
    Subject: test mail - please reply
    Thread-Topic: test mail - please reply
    Thread-Index: AcwZ/j5jcljS02i9S6K5tHCgppnF1A==
    Message-ID: <4BA9FDE58FCC87499C76D2776D34E5360A842A0C79@SBS2008.tgbdom.local>
    Accept-Language: en-US
    Content-Language: en-US
    X-MS-TNEF-Correlator: <4BA9FDE58FCC87499C76D2776D34E5360A842A0C79@SBS2008.tgbdom.local>
    MIME-Version: 1.0

    This only affects one specific domain.

    Does this help?

    Many thanks.

    Author Comment

    I forgot to mention that the report indicates it is generated by our own server rather than the destination.
    LVL 22

    Expert Comment

    by:Matt V
    From the NDR it looks like your own server is the one failing the delivery.  Do you have anything configured on your server for the domain that might lead your server to believe it is a local address?

    Author Comment

    No - not that I am aware of. I installed the server and have not made any non standard changes to the config. It all works fine apart from this one domain.
    LVL 56

    Accepted Solution

    This is still an issue on their end. And yes, your server is the one generating the NDR. This is how mail servers work. Think of two mail servers as a conversation. Here is an example.

    First, the setup. Many of my clients are in rural areas. Even the ones with broadband may have unstable connections, so it is not uncommon for them to use their ISP as a backup mail host or to purchase a backup mail host service.

    Now, let's say you wanted to email one of my clients while their SBS server was "offline" for whatever reason. Your server will try to contact the SBS server. That fails. So it polls the next MX record, which is the backup MX service. Your server contacts the backup MX service, achieves a connection and then has its normal SMTP conversation with "from" and "to" addresses. The backup service is literally just a placeholder, and will forward all mail to the SBS server when back online. So, let's say you did a typo and sent an email to "" instead of "" ....the backup MX server will accept that email address.

    SBS comes back online, the backup server attempts to deliver mail, SBS says "there is no" and the *backup* MX server is responsible for generating the NDR since it is the server that failed delivery. SBS never *accepted* delivery thus it is not responsible for generating an NDR.'s change the example a bit. Let's say SBS was up when you tried to email.

    You typed up the email in Outlook. You hit send. Your server accepts the email on your behalf. It contacts SBS, starts the SMTP conversation, and my SBS server reports an error that "" is an invalid address. My server reported the error *during* the connection, thus the message was never accepted and my server does not generate an NDR.

    Your server, having accepted the message from outlook, now must somehow let you know there was an error, so *it* is the responsible server for generating an NDR.

    Thus, it is *common* for the error to be on the receiving end, but the server generating the NDR to be your server. The ruel for NDRs is the last server to accept a message is responsible. If a server rejects a connection, for any reason, and that error is reported during the connection, it doesn't need to generate an NDR because it reported the error immediately.

    In this case, the connection between your server and the destination server is being rejected by teh destination server *at the time of connection* so the NDR must be generated by your server. But it isn't your server rejecting the connection. It is theirs.  And the information is pretty straightforward:
    #550 5.1.1 RESOLVER.ADR.RecipNotFound; not found #

    The recipient server is saying that the recipient is not found. This could be greylisting or some other anti-spam or anti-virus filtering on their end, but this is something you *need* to work with them to resolve.

    LVL 2

    Expert Comment

    Have you tried from OWA?
    Have you tried from a different user on the same network?
    Have you tried to a different person in the receiving company?
    Have you tried using Telnet to test connectivity?

    If it is working from an external source to that same email recipient it sounds like something either on your Outlook client or a connection between your servers.  I don't see where you have tested any of the items above (if I missed it I appologize) but you should try them all and report back.  It will help narrow down the possibility.  If any of the first 3 suggestions work I highly recommend looking at my previous comment as well.

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