Using an Azure VM as a DAG Witness Server

In Exchange 2013, it became possible to have a multi-site DAG configured in an active-active model by using a third site to host the File Share Witness (FSW). Since the release of Exchange 2013, Microsoft have expressed a desire to be able to use Windows Azure as the host of the FSW in this scenario. However, limitations in how site-to-site VPNs were configured in Windows Azure meant that this was not possible.

However, recent changes to Azure have removed this limitation. It is now possible to use Azure as the third site in this scenario.

The running of production Exchange servers is still not supported on Windows Azure so it is still not possible to stretch a DAG to include a Windows Azure site.

More details can be found at

Enhanced SPAM Protection for EOP

Exchange Online Protection (EOP) has recently been extended to provide improved SPAM protection.  The new functionality includes DMARC (Domain-based Messaging and Reporting Compliance) and DKIM (Domain Keys Identified Mail) for IPv4.  EOP has supported DKIM for IPv6 for a while.

DMARC uses the SPF framework to check the 5322.From address.  This is the address that appears in the e-mail client.  Traditional SPF only checks the 5321.MailFrom address.

DKIM allows a client to insert a digital signature into the header of a SMTP message.  This signature can then be verified against the Public key of the purported sending domain.

More details can be found at

Latest Exchange Updates (December 2014)

Microsoft have released the latest updates to Exchange.  The updates are:

  • Exchange Server 2013 Cumulative Update 7
  • UM Language Packs for Cumulative Update 7
  • Exchange Server 2010 SP3 Update Rollup 8
  • Exchange Server 2007 SP3 Update Rollup 15


Exchange 2013 Cumulative Update 7 includes updates to:

  • Public Folder Hierarchies (up to 250,000 folders)
  • OAB Distribution improvements
  • Backup improvements

This update will update the Active Directory Schema.

More details can be found at the following link