OTRS is creating new tickets when it should be updating a ticket

[klabarre]

My client uses ZenDesk and we'd like to set it up so that he creates a ticket in his system, which in turn sends an email to our OTRS helpdesk. This should create a ticket in OTRS and we can then deal with it, respond, etc. Everything seems to be working, except for the fact that every response to update the ticket from ZenDesk creates a NEW ticket instead of updating an existing ticket in OTRS. I'm guessing there is something in the email headers that's triggering this? What needs to be done to get this to work properly?

[reneeb]

The other system should keep your ticket number in the subject. Or you could check these Sysconfig options in Ticket -> Core::PostMaster:

* PostmasterFollowUpSearchInReferences
* PostmasterFollowUpSearchInBody
* PostmasterFollowUpSearchInAttachment
* PostmasterFollowUpSearchInRaw

You need to know if Zendesk uses anything to find out to which ticket the mail belongs to...

[reneeb]

Or maybe you can use the "ExternalTicketNumberRecognition" feature... then you can store Zendesks ticket number in a dynamic field.

[schulmann]

What needs to be done to get this to work properly?

The ZenDesk should set the smtp header "In-Reply-To" or "References" accordingly (RFC 5322 Chapter 3.6.4).