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I added a 10GB NIC to a SQL server which is connected over to a backend storage using ISCSI. I would like to force traffic going to a certain IP address/host to use the 10gb NIC, while all other traffic should continue to use the 1GB NIC.

The 10gb nic is configured using a private network. So far I have added a entry in the host file to the host I want to go over the private network and when I ping the host, it does return the private IP, but I'm still finding traffic going to the 1gb pipe.

How can I force all traffic to this host to use the 10gb interface? Would the best approach be a static route?

route print
Dest        NetMask     Gw                  Interface          Metric

0.0.0.0     0.0.0.0     160.205.31.254       160.205.31.26     266  

0.0.0.0     0.0.0.0     160.205.31.254       172.31.33.72      266



10gb NIC

IP 172.31.33.72

mask 255.255.255.255.0

GW 160.205.31.254


1gb NIC

IP 160.205.31.26

mask 255.255.255.0

gw 160.205.31.254

I want all traffic to 160.205.32.16 to use out the 10GB NIC.

  • What is your goal here? Why do you want traffic to 160.205.32.16 to go through the 10Gbps NIC? What is at 160.205.32.16? Is that your storage array? If so, you're doing it wrong. If 160.205.32.16 is your storage array and the 10Gbps NIC is the NIC connected to the storage array then the 10Gbps NIC should have an ip address in the same network as the storage array (160.205.32.x). – joeqwerty Nov 02 '13 at 18:01

2 Answers2

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If you perform a route print from the command prompt then you'll see a list of routes and their metrics. 0.0.0.0 denotes the Default Route, so if traffic is going through both NICs then I'd say you either:

1) Have a default gateway set on both NIC's - this is bad, so remove the DFGW from the second.

2) The other traffic which is going through NIC2 is on the same subnet as the NIC's IP. Windows would never route traffic on a different subnet through a NIC which is not on that subnet, or that doesn't have a gateway set (Or a static route)

I'm not understanding your position well enough to offer you specific advice. Could you update your question with the IP configuration of both NIC's and what IP's need to go where.

Dan
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  • Thanks for your reply. I updated it for clarity and included the info you requested. –  Nov 02 '13 at 17:24
  • @Stoicpoet Okay, something isn't right. Firstly, you have two default gateways which is a bad configuration. However, the second problem is that 160.205.31.254 is on a different subnet to the IP - this won't work either. – Dan Nov 02 '13 at 17:29
  • Also, do you really want to be routing your ISCSI traffic. To be honest, the more I read this question I'm unsure as to what you have. What is this 10GB NIC plugged into? Is it the same VLAN / Phsyical Network as the 1GB NIC? – Dan Nov 02 '13 at 17:33
  • 10gb is direct connected to backend storage via fiber. I didn't specify a gateway on 10gb NIC, it was automatically added. –  Nov 02 '13 at 17:40
  • Actually it is not. Gateways are not magically added in Windows. – TomTom Nov 02 '13 at 21:16
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  1. A Windows host cannot have more than one DG.

  2. The GW on the 10Gbps NIC is incorrect. A DG cannot be on a different network.

  3. In order for hosts to communicate with non-local hosts they send all non-local traffic to their DG. 160.205.32.16 is not local to either NIC so traffic to 160.205.32.16 will go by way of the DG. Since the DG on the 10Gbps NIC is wrong, all of the traffic to 160.205.32.16 is going out the 1Gbps NIC. If your intention is that you only want traffic to 160.205.32.16 to go through the 10Gbps NIC and you want all other non-local traffic to go through the 1Gbps NIC then you need to configure the DG on the 1Gbps NIC and leave the DG on the 10Gbps NIC empty and you need to have a device that can route the traffic for the 10Gbps NIC to 160.205.32.16 and you need to create a static route to 160.205.32.16 for the 10Gbps NIC.

  4. The hosts file is for name to ip address resolution. It has absolutely no bearing on the routing of traffic.

joeqwerty
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