I would e-mail a command to LISTSERV@xxx to see if the long header is generated on the outgoing or incoming side of Exchange (the response will be generated locally and will not have gone through the incoming side). My bet is that is happens on the incoming side and you can disable this header. Eric From: LISTSERV Site Administrators' Forum [mailto:[log in to unmask]] On Behalf Of Silcox, Matthew Sent: Monday, July 18, 2016 16:42 To: [log in to unmask] Subject: Re: Question regarding header size in emails Hey Nate, Did you ever get any leads on this? Do you know if it is, in fact, because of the massive EOP headers? I may be opening a Premiere Support Case with Microsoft if I don't find anything else on this. Respectfully, Matthew Silcox Senior Systems Administrator Client Infrastructure Group | Information Services Kent State University * 330.672.1290 * [log in to unmask]<mailto:[log in to unmask]> ________________________________ From: LISTSERV Site Administrators' Forum <[log in to unmask]<mailto:[log in to unmask]>> on behalf of Silcox, Matthew <[log in to unmask]<mailto:[log in to unmask]>> Sent: Monday, July 11, 2016 5:08:02 PM To: [log in to unmask]<mailto:[log in to unmask]> Subject: Re: Question regarding header size in emails We're seeing this, as well. Also in Office 365. I thought it was because we were doing a Proof of Concept for a 3rd Party spam filtering appliance, and there were some extra headers tacked on for that, but it looking more like Office 365 is the culprit. Respectfully, Matthew Silcox Senior Systems Administrator Client Infrastructure Group | Information Services Kent State University * 330.672.1290 * [log in to unmask]<mailto:[log in to unmask]> ________________________________ From: LISTSERV Site Administrators' Forum <[log in to unmask]<mailto:[log in to unmask]>> on behalf of Eckstine, Nate <[log in to unmask]<mailto:[log in to unmask]>> Sent: Monday, July 11, 2016 4:59:04 PM To: [log in to unmask]<mailto:[log in to unmask]> Subject: Question regarding header size in emails Hi, we are running Outlook on the desktop and Office 365 with exchange in the cloud for email delivery. Email goes to an IIS install of Listserv, then to the Microsoft Exchange cloud install, then offer to the destinations. We have recently started getting a lot of this message in our daily monitoring reports. And the email to the recipient is not delivered. Last error: 5.6.0 552 5.6.0 Headers too large (32768 max) I have been testing the email headers here. https://testconnectivity.microsoft.com/ It does indeed look like the message header approached 32KB in a lot of listserv messages. I have a dozen or so entries like this in the header analysis. I am not even sure if they are necessary. But searching the web isn't pulling up a lot of info on the X-command configuration. Technet fairly skimpy also. X-Microsoft-Exchange-Diagnostics-untrusted 1;BD2PR09MB8883;23: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 Has anyone seen anything like this? One suggestion has been is to email the destination email admins and ask them to raise their max header size. Another suggestion was to reinstall the connectors this system uses to place rules on the outbound emails. Thanks nate ________________________________ To unsubscribe from the LSTSRV-L list, click the following link: http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTSRV-L&A=1 ________________________________ To unsubscribe from the LSTSRV-L list, click the following link: http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTSRV-L&A=1 ________________________________ To unsubscribe from the LSTSRV-L list, click the following link: http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTSRV-L&A=1 ############################ To unsubscribe from the LSTSRV-L list: write to: mailto:[log in to unmask] or click the following link: http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTSRV-L&A=1