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SMTP Error 452 Too many recipients

    Question

  • We are using Exchange 2007 at a school to send email to parents.  When we send out email to all parents we get an error back from yahoo:  452 Too many recipients.

     

    We have 34 recipients on the list.

     

    Is there a way to configure Exchange SMTP outbound to break this up so it only sends to say 10 at a time?

     

    Thanks,

     

    Glenn

    Monday, November 12, 2007 8:10 PM

All replies

  • If you didn't change it, that shoudnt'd be a problem. Are you sure its your exchange server kicking the NDR and not a recipients server?

     

    Monday, November 12, 2007 9:37 PM
  • The error is coming from the recipients server back to our exchange server.  It appears yahoo has a limit for maximum recipients for a single message and we have 34 on our distribution list.  I'm hoping somewhere in exchange is a property that allows me to configure the maximum number of recipients to include with each SMTP connection session so it'll break it up into several sessions.

    Monday, November 12, 2007 9:46 PM
  • I"m kind of shocked but it doesn't seem like you can. I went through all the settings for the new-sendconnector cmdlet thinking you could create a custom send connector for yahoo, but nada.

     

    http://technet.microsoft.com/en-us/library/aa998936.aspx

     

     

    Monday, November 12, 2007 10:18 PM
  • This does seem like a huge omission, especially with folks like yahoo rejecting email when the sender list gets too big on the presumption it is spam.  It would seem that our only workaround would be to put the yahoo parent emails into two separate aliases and have the secretary send emails 5 minutes apart.
    Monday, November 12, 2007 11:01 PM
  • Here's more info on the problem after looking at the logs a bit more.

     

    When we send to yahoo with 34 recipients, the first recipient is accepted and all the rest are rejected as 'too many recipients'.  Exchange then tries again with the remaining users and one more email is accepted.  In our case it does this three times and then hits a case where the first

    yahoo email address is a bad address.  Yahoo comes back with an error for this address and 'too many recipients' for all the others.  It then gives up and does not try to send the remaining addresses.

     

    Being able to control the max number of recipients per smtp session would be one fix to this problem as I could set it to something like 10 so that even if one recipient is rejected, the others would not also get rejected as having 'too many recipients'.

    Tuesday, November 13, 2007 5:16 PM
  • I hate it when a question is responded with another question.  Why bother?
    WC
    Wednesday, November 10, 2010 5:26 PM
  • On Wed, 10 Nov 2010 17:26:47 +0000, Warren Chu wrote:
     
    >I hate it when a question is responded with another question. Why bother?
     
    I don't know. Why?
    ---
    Rich Matheisen
    MCSE+I, Exchange MVP
     

    --- Rich Matheisen MCSE+I, Exchange MVP
    Thursday, November 11, 2010 12:46 AM
  • Being able to control the max number of recipients per smtp session would be one fix to this problem as I could set it to something like 10 so that even if one recipient is rejected, the others would not also get rejected as having 'too many recipients'.

    Hi Glenn,

    I have the same problem. I have one user that used to broadcast to hundreds of recipients and most of them to Yahoo mail. And whenever the recipients are to yahoo.com, I saw a lot of "452 Too many recipients" in SMTP log. I wonder how to set max recipient per smtp session to yahoo.com...? Can you please tell me..? I am using Exchange 2010.

    Thanks a lot for your help.

    Regards,

    Hendhy

    Tuesday, January 07, 2014 8:27 AM
  • I don't know that Exchange 2010 has any way to control the number of RCPT TO commands sent in a single session.

    In any case, a 4xx status message isn't really an "error". At least not one that will cause a failure. Any 4xx status is one that can be retried. The recipients that weren't accepted in the 1st attempt will be tried again in the 2nd, and the ones not accepted in the 2nd will be tried in the 3rd, etc.

    If you're really bothered by this you can use a *nix server running, say, Postfix and configure it the way you think it should work. The problem is that not everyone follows the RFCs and allows at least 100 RCPT TO commands for a single message. You may wind up setting the number of recipients to the least common denominator, and that may be as low as two!


    --- Rich Matheisen MCSE&I, Exchange MVP

    Tuesday, January 07, 2014 10:24 PM