Hello, I have installed in my organization exchange 2010 with DAG. excahnge1 - ip1 exchange2 - ip2 DAG - ip3 Everything works fine, but when I stop IIS from one server (ip1) the webmail page is not found. It seems that DAG is not working for webmail ... What shoud I do to make webmail work in case one of two mail server fails ? Thank you.

Hi Robert, The recommendation for a two-node multi-role DAG is to use a hardware load balancer to load balance the CAS Array (which you probably need to create and set on your DBs) and the Web services, such as OWA (Webmail), EWS, OAB, ActiveSync, Autodiscover. KEMP technologies do pretty much the cheapest, decent, hardware load balancers and have easy to set up models for Exchange, including virtual ones. If you dont' use a load balancer, you are left with DNS round robin (one name, 2 A records) for 2 node DAG "load balancing". In this scenario, when a server fails, you need to consider removing it's round-robin record for the failed server from DNS; i.e. it's not great. SteveSteve Goodman Check out my Blog for more Exchange info or find me on Twitter

Steve is correct DAG does not load balance your web services. Since you have all roles on each server you can't utilize windows NLB in conjunction with DAG since you're already utilizing windows clustering services. You need to resort to Hardware load balancer or round robin DNS. Exchange 2010 RTM High Availability Load Balancing Options http://www.shudnow.net/2010/03/17/exchange-2010-rtm-high-availability-load-balancing-options/James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi, Here is some articles for you Configuring NLB for Exchange 2010 CAS Load Balancing http://blogs.kraftkennedy.com/index.php/2009/11/25/configuring-nlb-for-exchange-2010-cas-load-balancing/ Exchange 2010 RPC Client Access Service and the ClientAccessArray http://blogs.kraftkennedy.com/index.php/2009/09/09/exchange-2010-rpc-client-access-service-and-the-clientaccessarray/Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.