HI, we have NLB between 2 HUB/ CAS one of the them is virtual.the problem we face is when virtual HUB/CAS restart, the Physical HUB/ CAS not responding until the virtual up and running the the physical come to live after 6 minute.

Hi hodhod, Just so I have a better understanding of the issue, is your NLB a hardware NLB (KEMP, F5, etc.)? Also, by not responding, are users not able to access thier email data? ThanksChris Crandall - CB5 Solutions Exchange 2010 MCM - Office 365 MCM - MCT cbfive.com

windows NLB not hardware NLB. the user can't access to email because the outlook ask password.

any help Plz

Hi , Please test if you can access CAS via virtual ip or address. If no, please refer to the following article. Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode: http://blogs.technet.com/b/networking/archive/2009/01/15/unable-to-connect-to-windows-server-2008-nlb-virtual-ip-address-from-hosts-in-different-subnets-when-nlb-is-in-multicast-mode.aspxWendy Liu TechNet Community Support

Wendy this is not may case

when i change NLB from Unicast to Multicast it works fine. but i face new problem i can't open OWA FROM VIRTUAL IP OR FQDN