Exchange Online Fiddler Extension 1.0.60

The Exchange Online Fiddler Extension (EXO Fiddler Extension) version 1.0.60 is now available for download: This version adds significant functionality in the authentication space. An authentication column has been added giving key information on which sessions contain authentication headers / data. An ‘Office365 Auth’ inspector tab has been added showing more detailed information on authentication….


Exchange Online Fiddler Extension 1.0.50

Following on from my earlier post we have now made significant improvements to the extension and have just made version 1.0.50 available. Improvements in this new version include: Performance troubleshooting enhancements to the inspector tab. — See how long the Exchange Online server took to respond to requests. Updates to the rule set, new scenarios…


Introducing the Exchange Online Fiddler Extension

Working in support we deal with a lot of organisations which are migrating from Exchange On-Premise to Exchange Online. We spent plenty of time troubleshooting if Outlook has difficulties connecting to cloud mailboxes or on other related issues. We continually use tools such as The Support and Recovery Assistant (SARA), particularly useful to detect client based issues…


Troubleshooting Users: Script to pull all user data

I have worked a number of support cases where this script has been useful for pulling just about any data available from a user object. Ideally you will want to run this from a PowerShell window connected to both Microsoft Online and Exchange Online PowerShell modules. This script prompts for the User Principal Name of…


Troubleshooting Retention: Script to pull user policy and tags

I have worked a number of support cases where this script has been useful for pulling the retention policy, tags and all associated information to determine how the retention policies have been configured for a given user by their Office 365 administrator. See for the script description and to download.


Fiddler capturing and decrypting traffic on a different network

Having recently worked through a number of Exchange ActiveSync support cases it was necessary to setup a Fiddler proxy on a different network than the mobile device I was testing with. In my working scenario I setup a Windows client hosted as an Azure hosted virtual machine with Fiddler installed on an internet accessible IP…


Office 365 Dynamic Distribution Groups Filtered by On-Premise Organization Unit (OU).

I have been asked a number of times if it is possible to create Dynamic Distribution Groups in Office 365 filtered by the On-Premise Organization Unit (OU). I recently discovered a method to achieve this with some collaboration with a couple of colleagues. Essentially we need to create an inbound synchronization rule in AADConnect to…


Exchange Online Cross Tenant Calendar Free/Busy Availability Information

I was recently asked how to enable cross tenant calendar lookup, for arranging meetings, where two organizations are running their email services in Exchange Online. This happened to be something I had not thought about before, however in a company merger situation this would be an invaluable tool. Fortunately within Exchange Online the building blocks…


Hybrid Configuration Wizard – DataStrings.InvalidSmtpDomainName(domain) error connecting to On-Premise Exchange

I recently ran into an issue with a customer who was running the new Hybrid Configuration Wizard (, where the tool was unable to connect to the Exchange On-Premise environment, with the error DataStrings.InvalidSmtpDomainName(domain). The underlining cause was configuration data remaining from a decommissioned Exchange server, within the Exchange configuration in Active Directory. Once this configuration was…