NLB on multiple NICs

I have two webservers, web0 and web1, running windows 2000 AS, SP4, etc. We have two internet connections a cable and DSL connection both firewalled and routed by their own netscreen. Right now I serve a website from both webservers using round-robin DNS. I would like to still use round-robin to alternate back and forth between the cable and DSL but would like to enable NLB on both NICs. It seems that the NLB settings are for both NICs though.

There are two NICs because of the two gateways and some existing network infrastructure.
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You can't do NLB with the two NIC's on two different networks.
What is your real goal?
bbaoIT ConsultantCommented:

Lets listen what MS talks about NLB at first:

Network Load Balancing, a clustering technology included in the Microsoft® Windows® 2000 Advanced Server and Datacenter Server operating systems, enhances the scalability and availability of mission-critical, TCP/IP-based services, such as Web, Terminal Services, virtual private networking, and streaming media servers. This component runs within cluster hosts as part of the Windows 2000 operating system and requires no dedicated hardware support. To scale performance, Network Load Balancing distributes IP traffic across multiple cluster hosts. It also ensures high availability by detecting host failures and automatically redistributing traffic to the surviving hosts. Network Load Balancing provides remote controllability and supports rolling upgrades from the Windows NT® 4.0 operating system.

The unique and fully distributed architecture of Network Load Balancing enables it to deliver very high performance and failover protection, especially in comparison with dispatcher-based load balancers. This white paper describes the key features of this technology and explores its internal architecture and performance characteristics in detail.

OK, NLB works with Windows cluster, of Windows 2000 AS. so I just want to confirm this at first: what are the OSes for your two web server? Do they act as one cluster? If it is not, I dont think you can get points from NLB for your senario.
bbaoIT ConsultantCommented:
sorry, you are using W2KAS, hehe. :)
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GTIMANiacAuthor Commented:
As stated I am running windows 2000 AS, SP4.
There are two NICs in each machine one with a gateway of the cable network, the other with a gateway on the DSL network.

Right now I use round-robin DNS to alternate between DSL/Cable, 4 IPs, 2 Cable, 2 DSL, 1 of each per server.
I would like to setup NLB for DSL and for Cable. The round-robin is to protect against a connection going down, and the NLB is to distribute the load between the two servers. I get the feeling it is not possible.

WEB0  <-> Netscreen <-> Cable  IP of web0  <-> Netscreen <-> DSL  IP of web0

WEB1  <-> Netscreen <-> Cable  IP of web1  <-> Netscreen <-> DSL  IP of web1
I don't think that NLB is what you're looking for...
What you want is something like Cisco's LocalDirector load-balancer.
You have one public IP address, with multiple web servers on private IP addresses, and the LD distributes the load accross the servers depending on how you want to do it. for example you can use round-robin, or least busy. It also handles things like sticky connections...
Any comments?
GTIMANiacAuthor Commented:
Comments as far as what?

I should have mentioned that I am very aware of hardware based solutions from F5, Cisco and Radware. The point is to try to do this with existing hardware or with a minimal purchase. For the price of a hardware load balancer I could probably colo these servers for a very long time.

I am thinking that I will take advantage of the OSless PE on sale at Dell and build a second cluster, one cluster for each Network and I still am only out of pocket another 1200 bucks.
bbaoIT ConsultantCommented:
GTIMANiac, any update?
GTIMANiacAuthor Commented:
Here is what I did.

I setup a freeBSD box as a router, with 3 NICs. One NIC connected to the Cable Netscreen, One NIC connected to the DSL Netscreen the third NIC Connected to the switch that all the servers connect to. I setup IPFW on the BSD Box with rules that allow it to act as the gateway for all my networks and it will route traffic out the proper interface according to the source IP.

Then I setup multiple IPs in NLB. I did move to 2003 with a new group of servers, but the setup is the same as it was on the 2000 servers. I still use two NICS one for the Cluster and one for normal network operations.

So far it is rock solid.
bbaoIT ConsultantCommented:
good job! i think it is good to make your question as a PAQ to help other people later. cheers, bbao
PAQed - no points refunded (of 250)

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