Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

LucasICTSOL — Thu, 31 Mar 2011 14:36:08 GMT

Hi Guys,

many people have the same problem with Unicast mode, I have this problem for a week and then i found a solution: the automatic nlb configuration autoconfigure network setting of the load balancing network adapter, but leave blanck the gateway setting on that adapter, so retype gateway in the NLB network adapter of all yours server windows inform you that multiple adapter setting is not good etc... -> apply. Now you are able to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Unicast Mode

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Savio F — Sat, 01 May 2010 10:08:38 GMT

Hi Guys,

I have the same problem, we have 2 CAS/HUB Windows 2008 servers running Exchange 2007 on a vmware infrastructure. We also had the same prob of clients not able to ping to the NLB IP or OWA. Instead if we add a proxy they are able to do so. Logged to MS and configured NLB to use multicast, but now we are still not able to ping to the NLB VIP from other VLAN's. Can anybody help with a step-by-step solution to this problem

Savio.

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Vytas — Wed, 17 Feb 2010 23:01:29 GMT

http://support.microsoft.com/kb/960916 doesn't apply to R2...

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Saravanan N — Thu, 14 Jan 2010 22:01:20 GMT

Question

======

Hi,

Thanks for a good article - this helpt me solve an Exchange 2007 Client Access/Hub transport NLB cluster on W2k8.

I have two tips for others having this problem:

- If using redundant HSRP routers - both routers dedicated addresses as well as the virtual IP should be in the static ARP table.

- Use "netsh int ipv4 set neighbors "NICNAME" x.x.x.x xx-xx-xx-xx-xx-xx" instead of the ARP command. This way the entries remain after reboot without using "Scheduled Task" and other workarounds to repopulate the ARP cache.

With best regards

/ Stefan Alkman, Kontract

Answer: This issue has been resolved and here is the KB

http://support.microsoft.com/kb/960916.

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Jennifer Kasch — Wed, 16 Dec 2009 17:10:58 GMT

I still cannot ping the 2nd LAN adapter with my NLB on it. I can ping from inside the server...but that is it

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

GK — Sun, 26 Jul 2009 20:20:14 GMT

Was this included in 2008 SP2?

When I try to install the hotfix on an SP2 server, I get "Update does not apply to your system"

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Tyler — Tue, 23 Jun 2009 23:17:31 GMT

Good writeup. I've been troubleshooting this for the past couple of weeks, and this supports all of my findings so far.

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Sebash — Mon, 15 Jun 2009 12:52:49 GMT

Fixed with:

http://support.microsoft.com/kb/960916

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

Joe H. — Thu, 09 Apr 2009 06:09:12 GMT

I am seeing a problem with my 2 CAS as an NLB in Windows 2008 with two NICS config in Unicast mode. The problem is I can access the NLB cluster name for OWA internally. Externally/Internet I can't access OWA though I have NATed the public IP to the VIP of NLB.

I have Nated the dedicated IP of one of the CAS and I have no issues. Why doesn't VIP of NLB not NATing or responding correctly?

Any suggestions

re: Unable to connect to Windows Server 2008 NLB Virtual IP Address from hosts in different subnets when NLB is in Multicast Mode

michael — Thu, 26 Mar 2009 20:19:31 GMT

i am running MWS2003R2EE SP2 with XenServer 5 NLB 2 node cluster with VIP for 2 WI Servers and having the same problem. when you say "TCP/IP functionality has been changed in Windows Server 2008." is this true for my version of server 2k3?