System information

Appendix A: Advanced Device Configuration 377
Address Configuration for Connected Devices
The range of IP addresses is derived from the information shown in the
following table, which the administrator supplies to define a private subnet:
The system derives the range of addresses that can be used for talking to
devices by using the network portion of the OnBoard’s IP address and from
the private subnet netmask that the administrator specified.
When configuring a device, the administrator assigns the private subnet to the
device and assigns an IP address within the range specified for the private
subnet. The OnBoard uses the device’s IP address when talking to a device,
and devices use the OnBoard’s assigned address when talking the OnBoard.
When a private subnet is configured, the private subnet name is assigned to
the priv0 interface in the form priv0:private_subnet-name along with the IP
address assigned to the OnBoard in the form inet addr: OnBoardIPaddr.
If multiple private subnets are configured, multiple priv0:private_subnet-
name interfaces exist, each with its administratively-configured private subnet
IP address for the OnBoard. See the following examples for sample
ifconfig output:
• “Example 1: Private Subnet Configuration” on page 378
• “Example 2: Two Private Subnets and VPN Configuration” on page 381
Routing Requirements for Native IP Access
As documented in the AlterPath OnBoard User’s Guide, users who are
authorized for native IP access need to create a IPSec or PPTP VPN
connection before gaining native IP access.
Table A-11: Values for Configuring a Private Subnet
Field Definition
Private subnet name Any meaningful name chosen by the administrator, such as
privnet1.
OnBoard side IP
address
Devices use this address when communicating with the
OnBoard. The OnBoard uses this address when communicating
with devices. This address must be within the private subnet’s IP
address range.
Subnet mask Defines the range of addresses available on the private subnet.