I have a strange issue whereby emails from one particular domain become trapped in DATA status in the connections queue. This does not always happen and I have been unable to determine what causes the problem. I have been working with the administrator of the sending Exchange server but we can not identify any pattern. Once one email gets trapped, they start to pile up in the connections queue from this sender. 

I'm at a bit of a loss as to how to proceed with this problem. Can someone let me know what the DATA state is and maybe suggest why emails do not progress past this point. I'm guessing that the sending server is not correctly closing the connection or something. If tis is the case, I don't know what to tell them as they are not reporting this problem sending to other recipients. 

Any advice on how I should proceed with diagnosing this issue would be appreciated. 

Craig 

In SpamFilter's GUI, under the Settings tab, you will see a "Debug View" tab. In there you can enter an IP address with which all the SMTP traffic will be logged in that window for analysis. That may provide a clue as to what may be happening.

Alternatively, if you'd like to perform a Wireshark capture and then send us the data file we can look into this for you. If using Wireshark (which does not require a reboot to install, so it's one of our favorite capture tools), you'll want to apply a capture filter to capture only traffic to/from that specific host so as not to have a huge amount of data to capture. 

I'll also have a crack at the debug option.