How to properly configure NLB cluster in Windows 2008

Hi,

I have just tried to configure 2 node Windows 2008 NLB cluster and I run
into problem.
Until now I have successfully installed Windows Server 2003 NLB clusters. I
used 2 nic per node and unicast mode.

For example

Node1 Node2
Pub Interface (default) Pub
Interface (default)
IP:192.168.1.11/24
IP:192.168.1.13/24
GW: 192.168.1.1
GW: 192.168.1.1


NLB Interface*
NLB Interface*
IP:192.168.1.12/24
IP: 192.168.1.14/24
GW:-
GW:-
NLB IP Address: 192.168.1.15

*DNS registration, File Share client and server, NetBIOS over TCP/IP
disabled on this interface.

After configuring IP addresses I would run NLB manager and configure cluster
in unicast mode.


When I tried this on Windows Server 2008, I could not access NLB address
outside local subnet. Only when I configure DEFAULT GATEWAY on both NIC's,
NLB started working.

When I run network monitor I notices that in this configuration, Windows
2003 would always respond using Public LAN (source MAC address would be from
public NIC), no matter if i tried to connect to Public or NLB IP address.

In Windows 2008 if I tried to connect to Public IP, response packet would
had source MAC address from Public NIC and when I accessed NLB address then
source MAC would be from NLB NIC. For me this looks like change from 2003.

So how do we correctly configure unicast NLB cluster with 2 NIC's in Windows
Server 2008? Do we just add default gateway to NLB NIC?


Krunoslav

P.S.
When I tried to search for solution I found that other people had this issue.

P.S.S.
I posted this exact question on
http://social.technet.microsoft.com/...-87e24451f875/ and one of answers is

>We had a Similar issue with a 2008 cluster, which turned out to be a problem >with both Unicast and Multicast IGMP. We contacted premier support and worked >with them for quite a bit, to discover (or bet told that) this is a "feature" in 2008. >By default, IP forwarding is disabled. A cluster with multiple NICs will not respond >without a default gateway enabled. This can be worked around by entering the >following command from a command prompt:

>replace the section in quotes with the name of the cluster NIC.
>--netsh interface ipv4 set int "Front-end" forwarding=enabled

Forrmating is not working correctly

Node1
Pub Interface (default)
IP:192.168.1.11/24
GW: 192.168.1.1

NLB Interface*
IP:192.168.1.12/24
GW:-

Node2
Pub Interface (default)
IP:192.168.1.12/24
GW: 192.168.1.1

NLB Interface*
IP: 192.168.1.13/24
GW:-

NLB IP Adress is 192.168.1.15

*DNS registration, File Share client and server, NetBIOS over TCP/IP
disabled on this interface

"Krunoslav Mihalic" wrote:

> Hi,
>
> I have just tried to configure 2 node Windows 2008 NLB cluster and I run
> into problem.
> Until now I have successfully installed Windows Server 2003 NLB clusters. I
> used 2 nic per node and unicast mode.
>
> For example
>
> Node1 Node2
> Pub Interface (default) Pub
> Interface (default)
> IP:192.168.1.11/24
> IP:192.168.1.13/24
> GW: 192.168.1.1
> GW: 192.168.1.1
>
>
> NLB Interface*
> NLB Interface*
> IP:192.168.1.12/24
> IP: 192.168.1.14/24
> GW:-
> GW:-
> NLB IP Address: 192.168.1.15
>
> *DNS registration, File Share client and server, NetBIOS over TCP/IP
> disabled on this interface.
>
> After configuring IP addresses I would run NLB manager and configure cluster
> in unicast mode.
>
>
> When I tried this on Windows Server 2008, I could not access NLB address
> outside local subnet. Only when I configure DEFAULT GATEWAY on both NIC's,
> NLB started working.
>
> When I run network monitor I notices that in this configuration, Windows
> 2003 would always respond using Public LAN (source MAC address would be from
> public NIC), no matter if i tried to connect to Public or NLB IP address.
>
> In Windows 2008 if I tried to connect to Public IP, response packet would
> had source MAC address from Public NIC and when I accessed NLB address then
> source MAC would be from NLB NIC. For me this looks like change from 2003.
>
> So how do we correctly configure unicast NLB cluster with 2 NIC's in Windows
> Server 2008? Do we just add default gateway to NLB NIC?
>
>
> Krunoslav
>
> P.S.
> When I tried to search for solution I found that other people had this issue.
>
> P.S.S.
> I posted this exact question on
> http://social.technet.microsoft.com/...-87e24451f875/ and one of answers is
>
> >We had a Similar issue with a 2008 cluster, which turned out to be a problem >with both Unicast and Multicast IGMP. We contacted premier support and worked >with them for quite a bit, to discover (or bet told that) this is a "feature" in 2008. >By default, IP forwarding is disabled. A cluster with multiple NICs will not respond >without a default gateway enabled. This can be worked around by entering the >following command from a command prompt:
>
> >replace the section in quotes with the name of the cluster NIC.
> >--netsh interface ipv4 set int "Front-end" forwarding=enabled

"Krunoslav Mihalic" <Krunoslav > wrote in
message news:09C63564-A5E9-4990-B5A0-...

> So how do we correctly configure unicast NLB cluster with 2 NIC's in
> Windows
> Server 2008? Do we just add default gateway to NLB NIC?

In 2008, you no longer need two nics to properly configure with Unicast. You
can now use a single NIC and it will all work well.

Thanks for info,

do you have any link to some document how to do this (unicast with single
NIC)?

Krunoslav

"Russ Kaufmann" wrote:

> "Krunoslav Mihalic" <Krunoslav > wrote in
> message news:09C63564-A5E9-4990-B5A0-...
>
> > So how do we correctly configure unicast NLB cluster with 2 NIC's in
> > Windows
> > Server 2008? Do we just add default gateway to NLB NIC?
>
> In 2008, you no longer need two nics to properly configure with Unicast. You
> can now use a single NIC and it will all work well.
>

"Krunoslav Mihalic" <> wrote in
message news:6AD3CF86-9676-4024-BCCA-...
> Thanks for info,
>
> do you have any link to some document how to do this (unicast with single
> NIC)?

No. It is pretty straight forward, though.


--
Russ Kaufmann,
MVP, MCSE: Messaging and Security, MCT, MCITP, MCTS and other stuff

ClusterHelp.com, a Microsoft Certified Gold Partner
Web http://www.clusterhelp.com
Blog http://msmvps.com/clusterhelp

Hm,

when I configure NLB with one NIC, NLB manager shows this message on startup

"Running NLB Manager on a system with all networks bound to NLB might not
work as expected.
If all interfaces are set to run NLB in "unicast" mode, NLB manager will
fail to connect to hosts.
See "Help and Support Center" for unicast communication limitation"

This does not sounds like recommended configuration.

Any comment?

"Russ Kaufmann" wrote:

> "Krunoslav Mihalic" <> wrote in
> message news:6AD3CF86-9676-4024-BCCA-...
> > Thanks for info,
> >
> > do you have any link to some document how to do this (unicast with single
> > NIC)?
>
> No. It is pretty straight forward, though.
>
>
> --
> Russ Kaufmann,
> MVP, MCSE: Messaging and Security, MCT, MCITP, MCTS and other stuff
>
> ClusterHelp.com, a Microsoft Certified Gold Partner
> Web http://www.clusterhelp.com
> Blog http://msmvps.com/clusterhelp
>

"Krunoslav Mihalic" <> wrote in
message news:52FDF136-E75E-47A1-8767-...
> Hm,
>
> when I configure NLB with one NIC, NLB manager shows this message on
> startup
>
> "Running NLB Manager on a system with all networks bound to NLB might not
> work as expected.
> If all interfaces are set to run NLB in "unicast" mode, NLB manager will
> fail to connect to hosts.
> See "Help and Support Center" for unicast communication limitation"
>
> This does not sounds like recommended configuration.

I am not able to replicate the message. Are you sure you are using Windows
2008 and not 2003?