SOSS uses a combination of a network identifier (either a network subnet or an explicit IP address) and a subnet mask to choose network interface that it binds to at service startup. The net_interface and subnet_mask parameters (located in the soss_params.txt file) control these two settings, respectively. See the Configuration Parameters topic in Online Help for documentation on these parameters.
By default, SOSS uses a subnet_mask of 255.255.255.0, which allows it to choose any local IP address on the class C subnet specified by the net_interface parameter. Selecting a network subnet instead of a specific IP address is useful when servers use DHCP or other dynamic means to obtain IP addresses on the subnet.
When the SOSS service starts, it scans the local host's network interfaces for one that matches the configured net_interface and subnet_mask parameters and binds itself to the first matched interface that it finds. For environments with two NICs on the same subnet, SOSS should be configured with stricter settings to ensure the desired network interface is selected. This is especially critical in environments where the two interfaces are rated at different network speeds and you intend to use a specific NIC.
If you want SOSS to exclusively use a specific address (For example, 10.0.4.149), you need to set the subnet mask so that only that one, specific IP address is used. There are two ways to accomplish this:
You can manually edit the soss_params.txt file. Set the net_interface parameter to 10.0.4.149 and set the subnet_mask to 255.255.255.255. After making those changes the SOSS service will need to be restarted before the host is able to join the store.
The other option is to use the SOSS Console to make the change. On the Host Configuration tab set the Net Interface Mask field to 255.255.255.255 and click the Apply button. After the service restarts, the Net Interface dropdown box will have 10.0.4.149 as one of the options to select. Once the desired IP address has been selected, click Apply again to save your changes.