Routing network traffic thru multiple NICs
Posted by Rob Burkindine on 04 January 2010 02:43 PM


This can be used to route traffic thru a specific NIC. A common scenario is a workstation with dual NICs, one is to access the agency network and the other connects to an AFIS network. This usually results in the AFIS traffic to route thru the wrong network, resulting in failures.


1. You need to create a static route on the machine you ftp'ing from to force it to go out the appropriate NIC.

2. Open a command prompt and enter the following command:

route add mask metric 1 if 2

(Of course this is specific to each network and the particular workstation. You need to tweak for your specific client.)

  • The first ip address is the AFIS (ex: DCJS) FTP server
  • The second is the mask
  • The third IP is the inside gateway
  • Metric 1 gives it 1st priority
  • If 2 is the interface number of the NIC configured for the Foray (agency) subnet.
  • You can get this be entering route print at the command prompt.

Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 1b 11 0f 24 67 ...... D-Link DFE-530TX+ PCI Fast Ethernet Adapter (rev.F) - Packet Scheduler Miniport
0x3 ...00 1c 23 8b 14 65 ...... Broadcom NetXtreme 57xx Gigabit Controller - Packet Scheduler Miniport

Note: In this case interface 0x2 is the Foray (agency) NIC which would be entered as "if 2"

3. After you run the route add command, verify be running route print again and look for the proper route:

Active Routes:
Network Destination Netmask Gateway
Interface Metric
20 20
20 20 20 1 1 20 20 20 30 20 20 1 1
Default Gateway:
Persistent Routes:

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