Hi, Environment: Exchange Server 2003 on Windows Server 2003 I am trying to troubleshoot this problem for some time. It seems incoming emails from LinkedIn are rejected. Here is my SMTP log for one of such transactions: #Fields: date time c-ip cs-username cs-method cs-uri-stem cs-uri-query sc-status sc-bytes cs-bytes time-taken cs-host cs(User-Agent) cs(Cookie) cs(Referer) 2011-02-03 13:09:43 69.28.147.155 mailc-ad.linkedin.com EHLO - +mailc-ad.linkedin.com 250 321 26 0 - - - - 2011-02-03 13:10:03 69.28.147.155 mailc-ad.linkedin.com MAIL - +FROM:<m-qXFzym9wZ3Q0wIHa-Iwk9Leblr@bounce.linkedin.com> 554 0 60 20015 - - - - 2011-02-03 13:10:03 69.28.147.155 mailc-ad.linkedin.com QUIT - mailc-ad.linkedin.com 240 25 60 20015 - - - - Note LinkedIn emails come from various servers in different IP subnets and the above is just one of them. There is no entry in my Exchange message tracking logs so it means it was not even attempting to deliver to the mailbox. I notice in the above SMTP log, it has sc-status 554 which means 'transaction failed.' I guess it's blocked by my mail server for some reason. So I checked my Deny List but saw its IP does not fall in any of the IP ranges I set up. I also have UCEContentFilter.xml set up to filter based on subject and message body but as far as I can tell, it's not blocking such messages. Will it get logged somewhere if it's filtered by content filter? Is there any other way to narrow down the problem (e.g., turning on even more verbose logging, other places to look for)? I also checked WIndows Server's Applications log but see no entries relevant to this issue. Thank you!

Are you using IMF for Exchange 2003?Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Yes. And I have some filtering. However, I checked against the words I set to filter but did not find any offending words. I used to have "LinkedIn" in IMF's UCEContentFilter.xml file but I've removed it. Must I restart some service such as SMTP service for it to take effect? Thanks!

So, the issue only happens to the incoming mail from LinkedIn? Please check the content in the NDR in the sender’s mailbox, and also the message headers of that NDR Please increase the diagnostic logging level on the transport components (Reference) James Luo TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

James, Yes, it's about incoming emails from only LinkedIn. I am not sure it's realistic to check sender's mailbox for NDR because these are automated messages from Linkedin servers and I don't think there will be NDR in his LinkeIn mailbox. However, LinkedIn does notify the member about bounced email saying the email has failed to deliver to his work emailbox. Thanks for the tips on logging. I increased the diagnostic logging level for Transport > SMTP from minimum to medium but OS's application log does not catch the rejected Linkedin emails. I am changing to it to maximum to see how it goes. I have tested by forwarding my LinkedIn email in my personal email box to my company emailbox and it arrived fine. So it means it is not the contents violation. The fact it does not show in message logs makes me suspect it's denied by connection filtering. If so, will diagnostic logging = maximum record such events? Thanks,

Quote: “because these are automated messages from Linkedin servers” Then, please ask sender to send the message directly from LinkedIn mailbox to exchange mailbox. The error information will help Quote: “I have tested by forwarding my LinkedIn email in my personal email box” Where is your personal mailbox, on the LinkedIn? Please add several LinkedIn IP addresses into the global accept list of the connection filtering, see if the issue still appears when the matched IP address sends the mailPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thank you all. It turns out it's the sender filtering blocking the incoming emails.