I have a strange issue with attachment size limit 15mb in a mixed mode environment (Exch 03 / Exch 07) and can't figure it out. All mailboxes have been moved to Exchange 07. send/receive connectors are set to 20mb. We have no problem of sending 20mb attachment to internal users but could not send/receive 15mb attachment to external users. By passing the smart host server doesn't solve the problem either. error msg: Delivery has failed to these recipients or distribution lists:abc@xyz.comThis message exceeds the maximum message size allowed. Microsoft Exchange will not try to redeliver this message for you. Please make the message smaller -- by removing attachments, for example -- and try sending it again, or provide the following diagnostic text to your system administrator.We are using Spamassassin and mimedefang with ClamAV on smart host server. All settings are set to 20mb limit. [PS] C:\Documents and Settings\jnguyen>Get-TransportConfigClearCategories : TrueGenerateCopyOfDSNFor : {5.4.8, 5.4.6, 5.4.4, 5.2.4, 5.2.0, 5.1.4}InternalSMTPServers : {}JournalingReportNdrTo : <>MaxDumpsterSizePerStorageGroup : 18MBMaxDumpsterTime : 7.00:00:00MaxReceiveSize : 20MBMaxRecipientEnvelopeLimit : 500MaxSendSize : 20MBTLSReceiveDomainSecureList : {}TLSSendDomainSecureList : {}VerifySecureSubmitEnabled : FalseVoicemailJournalingEnabled : TrueXexch50Enabled : TrueADSI Edit: submissionContLength = 20480 & DelivContLength = 20480What else I can check? Please help or any advice is really appreciated. Thank you,John

Do you have edge transport server in environment? If so then you may need to check limit on it with get/set-transportconfig. Get-TransportConfig (on edge server) Check it on send/receive connector from hub transport server to edge transport server or on send/receive connector from hub transport server to smart host Get-SendConnector Set-SendConnector "Connector Name" -MaxMessageSize 20mb References: Exchange 2007 - Message Size Limits Managing Message Size Limits

We are not using Edge server. Send/receive connectors are set at 20mb. I have no problem of sending to internal users. -jn

Hi, To find the root cause of this issue, please enable Message Tracking and provide the log on the forum. Through this, we can find the phase that the message stopped on the transmission. You can refer to the link as your reference. http://technet.microsoft.com/en-us/library/aa997984(EXCHG.80).aspx Thanks Allen

Hi Allen,Here is the msg tracking log. p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:12.0pt;font-family:'Times New Roman';} @page Section1 {size:11.0in 8.5in;margin:.9in 1.0in .9in 1.0in;} div.Section1 {page:Section1;} 2008-07-18T16:45:57.895Z,192.168.x.x (Exch07),,192.168.x.x (Exch07-CAS),Exch07-CAS,08CAB1D7A3E3B17E;2008-07-18T16:45:55.536Z;0,EXCH07-CAS\Default EXCH07-CAS,SMTP,RECEIVE,33453,<A6658EBB8DDF2F41B80F719C1052D93A53380B6A02@exch07.narus.com>,xyz@gmail.com,,22429837,1,,,FW: test 16mb,test@narus.com,test@narus.com,0cI: 2008-07-18T16:46:01.770Z,192.168.x.x (Exch07-CAS),Exch07-CAS,192.168.x.x(Exch03),EXCH03.narus.com,08CAB1D7A3E3B17F,Intra-Organization SMTP Send Connector,SMTP,SEND,33453,,xyz@gmail.com,250 2.1.5 xyz@gmail.com ,22429837,1,,,,,test@narus.com,2008-07-18T16:45:40.554Z 2008-07-18T16:46:02.224Z,192.168.x.x(Exch03),,192.168.x.x (Exch07-CAS),Exch07-CAS,08CAB1D7A3E3B180;2008-07-18T16:46:01.880Z;0,EXCH07-CAS\Default EXCH07-CAS,SMTP,RECEIVE,33454,<rcoI4m3zp000003a7@Exch03.narus.com>,test@narus.com,,1748,1,,,Delivery Status Notification (Failure),postmaster@Narus.com,<>,0bI:

Hi Allen,After analyzing the message tracking log, I found the problem within the hub transport server. Everytime we send out an attachment to external users, exchange 07 will add 35% overhead to the msg size. This is a bug in exchange 07 because this only happen when sending msg to external users. e.g Sending 14mb to external user = user receive18.9mb total msg size. (14mb + (14 * 35%)). I will report this bug to Microsoft. Thanks for your help,

I have the exact same setup with the same issue... turns out my send and receive connectors have a default MAX value of 10MB per message, I believe this was added on at some point... anyway, here is a great article with screen shots on how to change the value... I changed my message value to 40MB and left my attachment size at 25MB and everything is working now. I hope this helps. http://exchangeshare.wordpress.com/2008/04/24/exchange-2007-where-to-set-message-mail-size-limit/