Installing and Administering LAN/9000 Software

Chapter 6 151
Network Addressing
Configuring Gateways on Fixed-Length Subnets
Configuring Gateways on Fixed-Length
Subnets
Besides using the appropriate subnet masks, each gateway needs to be
configured so that it can properly route messages among the several
subnetworks. Following are descriptions of two types of routing: explicit
routing and dynamic routing. When using explicit routing, you must
specify the IP address of each gateway to which you are directly
connected. When using dynamic routing, you need to specify only the IP
address of one gateway, and the system learns the IP address of other
gateways from the specified gateway.
Explicit Routing
There are many ways to set up routing. For example, you might use the
route(1M) command or you may add the following entries to the netconf
file on Host A in Figure 6-9:
ROUTE_DESTINATION[0]=”net 192.6.12.128”
ROUTE_GATEWAY[0]=”192.6.12.36”
ROUTE_COUNT[0]=”1”
ROUTE_DESTINATION[1]=”net 192.6.12.96”
ROUTE_GATEWAY[1]=”192.6.12.34”
ROUTE_COUNT[1]=”1”
ROUTE_DESTINATION[2]=”net default”
ROUTE_GATEWAY[2]=”192.6.12.35”
ROUTE_COUNT[2]=”1”
The 1 in each ROUTE_COUNT entry specifies an indirect route. For
example, messages for the system on the 192.6.12.128 subnetwork will
first be sent to Host B (192.6.12.36), and from there they will be
forwarded to the destination system.
Dynamic Routing
Alternatively, and perhaps the easiest way to manage growth on the
192.6.12 network, you might add the following entries to each netconf
file.
Hosts A, B and C: