Office365 and Google DNS Servers

Many companies use the Google DNS servers ( and as forwarders to resolve internet addresses.

Whilst performing some exhaustive troubleshooting on Office365 & Outlook slowness & connection issues, we have uncovered incorrect addresses being resolved for EMEA customers.

When using Office365 in EMEA, is a CNAME record that should always resolve to either, or This means you access the servers closest to you, and don’t cross the Atlantic multiple times to get to your data.

Google DNS servers

I have seen multiple occurrences recently of Google’s servers resolving UK based clients to which causes mail opening times of between 3-8 seconds (depending on the message size) and a raft of other connection and disconnection issues.

I recommend not using Google’s name servers if you’re either using Office365 or rely on accurate name resolution, but either OpenDNS or the servers provided by your ISP.

I'll shortly post a powershell script in the downloads section that will send an email if any of your nameservers return a non-emea result.

Tony currently works at Cloudworks implementing Office 365 and Azure based projects.