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Manual DNS server override for a single domain

    Question


  • Hi I have a domain running server 2012 serving dns dhcp to 90 clients, within my dns role I have set up forwarder to point to “opendns” to apply internet site category filtering to me clients.

    I am also using office365 for all email on our network, recently Microsoft upgraded the service in the cloud and after this upgrade we had a dramatic drop in bandwidth for all the clients trying to access office365 exchange online mailboxes, after lengthy investigations I have pinpointed the problem back to my use of opendns on my network, if I change the server 2012 DNS forwarded to point to our ISP’s dns servers I regain full bandwidth to the office365 servers and all my outlook clients speed up back to the same speed I use to see prior to the Microsoft office 365 cloud upgrade around 1 month ago.

     

    Our company is located in Australia and I had a feeling that while pointing my network to opendns we may be getting directed to an office356 datacentre that is not meant for our region here in Australia, I did some test via http://www.opendns.com/support/cache/ and discovered that when I was using opendns my outlook clients are connecting to the hong kong,china IP’s listed in this report from  http://www.opendns.com/support/cache/

     


    While when I use my local ISP dns servers all me clients connect to the Singapore IP’s listed above.

    Ok so I know the reason why I now get slow bandwidth and I could just point my local domain DNS server forwarders to seek DNS from my ISP but then I will lose my content filtering that is provided via openDNS  and my company directors will not accept this.

    My question is can I somehow setup a manual rule on my domain controllers DNS server  to not use openDNS for “outlook.office365.com” domain name and instead use the ip’s listed in the Singapore column in the screen capture above ?  

    If this is possible any advice or instructions would be much appreciated J

    Wednesday, October 16, 2013 1:30 AM

Answers

  • Hi,

    create a conditional forwarder for OUlook.offic365.com and point it to ISP

    so that when clients query the DNS , it will check for the conditional forwarder and pass the request to ISP. for all other requests , the DNS will fall back to Forwarders.

    Wednesday, October 16, 2013 5:15 AM