We have set max receive size as unlimited  at organization level.  Organization Configuration > Hub Transport > Global Settings > Transport Settings > General tab

Also max message size is set as 50 MB for receive connector for emails coming from internet. But still users are not able to receive any email of more than 20 MB attachment. Senders are also not getting any delivery failure message. When i check the transport log it shows

This message won't be sent because it's too large.

550 5.2.3 RESOLVER.RST.SendSizeLimit.Org; message too large for this organization

Is it because the limit set at Organizational level? we have left max receive size field as blank in Transport Settings . Also why a Delivery failure message is not getting generated? PLease help

We have exchange 2010 SP3 .

Hi,

Check if ADSiteLink is also set to bypass the max size. Otherwise, set it also

Get-AdSiteLink | ft name,MaxMessageSize

ADSitelink is set as unlimited only. My worry is why exchange is not generating NDR even though in transport logs it is showing as :

This message won't be sent because it's too large.

550 5.2.3 RESOLVER.RST.SendSizeLimit.Org; message too large for this organization

We have set max receive size as unlimited  at organization level.  Organization Configuration > Hub Transport > Global Settings > Transport Settings > General tab

Also max message size is set as 50 MB for receive connector for emails coming from internet. But still users are not able to receive any email of more than 20 MB attachment. Senders are also not getting any delivery failure message. When i check the transport log it shows

This message won't be sent because it's too large.

550 5.2.3 RESOLVER.RST.SendSizeLimit.Org; message too large for this organization

Is it because the limit set at Organizational level? we have left max receive size field as blank in Transport Settings . Also why a Delivery failure message is not getting generated? PLease help

We have exchange 2010 SP3 .

The send and receive size limits set at the org transport level should match.

The Max send size is set as 20 MB but receive size is set as unlimited at Organization Configuration. IS there any particular reason why both are set as same? Do you see this causing the problem?

The Max send size is set as 20 MB but receive size is set as unlimited at Organization Configuration. IS there any particular reason why both are set as same? Do you see this causing the problem?

For anonymous senders ( messages from the internet), the value used will be the lower of the two, so if you want to allow 50MB message sizes from the internet, set both the send and receive to 50MB.

Thanks Andy for your reply. I was trying to find this explanation on internet but was not able to find so. Can you refer to me some microsoft technet article.  Also 550 5.2.3 RESOLVER.RST.SendSizeLimit.Org is this error indicates that it is related to only Organization Configuration or due to some restriction on any of receive connectors? 

Thanks Andy for your reply. I was trying to find this explanation on internet but was not able to find so. Can you refer to me some microsoft technet article.  Also 550 5.2.3 RESOLVER.RST.SendSizeLimit.Org is this error indicates that it is related to only Organization Configuration or due to some restriction on any of receive connectors? 

https://technet.microsoft.com/en-us/library/bb124345%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396

The exceptions for the user limits only apply to message exchanges between authenticated users. If a message is sent to or received by a recipient on the Internet, the organizational limits will be applied. For example, assume that you have an organizational message size restriction of 10 MB, but you have configured the users in your marketing department to send and receive messages up to 50 MB. These users will be able to exchange large messages with each other, but they still wont be able to receive large messages from Internet users because such messages will be coming from unauthenticated senders.

https://support.microsoft.com/en-us/kb/322679

Note  All Internet e-mail messages use the global setting for limits on sending and on receiving.  The message categorizer evaluates the sender's sending limit and the recipient's receiving limit.  In example 2 earlier, a user with a user mailbox limit of 3 MB could receive messages from another user with a 3-MB sending limit.  Because Internet users use the global setting, they can send only a 2-MB message.

http://exchangepedia.com/2007/09/exchange-server-2007-setting-message-size-limits.html

Do individual message size limits bypass the Organization message size limits?

This is perhaps one of the most misunderstood part of message size limits, and therefore a frequently asked question: when you specify individual message size limits for a recipient, does it override other message size limits in your Exchange organization?

In a nutshell, setting higher message size limits on an Exchange recipient bypasses the maximum message sizes in the Exchange Organization configuration, but only for internal messages, not for messages sent to or received from the Internet and other unauthenticated sources.

Remember, for a message to be delivered successfully, the message size must be within the max message size limits applicable to both the sender and the recipient. Because the identity of  unauthenticated or anonymous senders and recipients cant be established (because theyre unauthenticated!), the organizational limit applies.

and yes, that NDR implies the org limit is the issue.

Thanks Again Andy for such a detailed explanation. Its really very helpful. One last question why NDR is not generating in for this? Only when checking the transport server log we are able to see 550 5.2.3 RESOLVER.RST.SendSizeLimit.Org; message too large for this organization.

Should not be a NDR is generated for this?

Hi ,

Thank you for your question.

As no NDR, we could check the following steps:

1.        Navigate to EMC-> Organization Configuration->Hub Transport->Remote Domains->Properties->message Format, then make sure we have checked Allow Non-Delivery reports as the following snapshot:
2. 
   
3.        If it has checked, we could if there is a transport rule to block it.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Thanks Again Andy for such a detailed explanation. Its really very helpful. One last question why NDR is not generating in for this? Only when checking the transport server log we are able to see 550 5.2.3 RESOLVER.RST.SendSizeLimit.Org; message too large for this organization.

Should not be a NDR is generated for this?

Yes, it should be. Does Exchange accept messages directly from the internet or is there something between it and the internet like another SMTP gateway or anti-spam provider etc...

We have a proof point gateway which accepts messages from the iinternet and after performing hygiene check passes the email to hub transport server.

We have a proof point gateway which accepts messages from the iinternet and after performing hygiene check passes the email to hub transport server.

Ok, optimally, Proof Point should have the 50MB limit set there. ( Or whatever max limit you want).

That way, when external recipients send to your org, the check is done by Proof Point, and it will reject messages that are oversized. That way, the external senders mail server is responsible for generating the NDR.

If that is not possible, once Proofpoint accepts the message for your org and then attempts to send an oversize message, then Exchange will reject the message and its up to Proofpoint to generate the NDR. If that isn't happening, then I would look at the ProofPoint config. logging and/or ask their support.

 

Thanks Andy for your replies. It really helped me a lot.