Hi, I have many machines, each machine has two NICs, each NIC connect to different segment, one is for Production segment, another one is for backup segment, all unknown traffic should be routed to Production segment. AD and all major traffic are in Production segment, backup segment is only for backup traffic ONLY. e.g. NIC1 - Production Segment IP - 10.10.10.1 / 24 Gateway - 10.10.10.254 NIC 2 - Backup Segment IP - 192.168.1.1 / 24 I am not sure just the above configuration is enough or not. Should I need to move up the NIC 1 to higher level in Adapters and Bindings? And any other thing i need to aware to prevent any packet loss? Thanks so much.

With the configuration that you described all traffic destined for any host on the 192.168.1.1/24 network will leave out of adapter #2. All other traffic will leave out of adapter #1. If you have any other target systems on the remote side of 192.168.1.1 (if you do have a router on that subnet), then you'll need to add static route(s) on the multihomed systems to get there via 192.168.1.1 NIC, otherwise, the traffic will go out of NIC1. The other issue you have to be concerned with is having the backup systems communicate with these hosts over the 192.168.1.x network. If your backup infrastructure is also multihomed, then when the backup servers try to connect to their clients, they will use DNS to do so. If the record comes back with a 10.10.10.x address, they will use their 10.10.10.x NICs to send out traffic. this is the tricky part. Visit: anITKB.com, an IT Knowledge Base.

Thanks JM, There is no remote side connected to Backup Segment. That means no need specific configuration required. Just wonder when I need to adjust the configuration in Adapters and Bindings? Thanks so much.

Hi MyGardenia, Thanks for posting here. > all unknown traffic should be routed to Production segment. AD and all major traffic are in Production segment, backup segment is only for backup traffic ONLY. > There is no remote side connected to Backup Segment. Then it should no more configuration needs since you have set the only default gateway for NIC1 and please also make sure have set proper routing entry to 192.168.1.0/24 subnet for each host. Please also take look the articles below: Source IP address selection on a Multi-Homed Windows Computer http://blogs.technet.com/b/networking/archive/2009/04/25/source-ip-address-selection-on-a-multi-homed-windows-computer.aspx Default Gateway Configuration for Multihomed Computers http://support.microsoft.com/kb/157025 Thanks. Tiger Li Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

What you are attempting seems a good idea on paper, but if fact it rarely works. As [JM] pointed out, a particular app will not use a particular network just because it is there. Your backup data will only use the 192.168. network if the target machine resolves to a 192.168. IP address. How are you going to force that to happen? If the software uses DNS or NetBt to find the address of the backup server it will probably come up with a 10. address. If it does, it will communicate on the 10. network. Bill

Thanks Bill. We are discussing the method. 1. another set of server name in DNS 2. local host file seems only has this two ways.

Thanks Tiger, Much understand the behavior especially the source IP selection. Thanks.

Again, this is very tricky. The issue is going to be to somehow force the backup system to communicate with the hosts over this 192.168.x.x segment. If the backup infrastructure is isolated, a seperate DNS will work as expected. However, most of these backup systems require communication with Active Directory and other systems on your production network. IF this is the case, the seperate DNS isnt going to be an option. HOSTS is also an option if you have very few backup clients. Otherwise, the managment of this is unbelievable. As you can see, unless you have a small network, its very difficult to implement on Enterprise class systems. Visit: anITKB.com, an IT Knowledge Base.