You have a choice of several addressing schemes for PPP, depending on your configuration type. Before you edit the asppp.cf file and hosts database, you must decide on the appropriate addressing scheme for your configuration. These schemes include:
Using the same IP addresses for the PPP endpoints as is assigned to their primary network interface in their local /etc/inet/hosts files
Assigning a unique IP address for each PPP endpoint
Assigning a new network number for the network created by the PPP link
This addressing scheme is appropriate for point-to-point links only. In this scheme, you specify the addresses of the primary network interface for each endpoint. (See Chapter 1, Overview of Network Administration, for more information about the primary network interface.) These endpoints might be:
Two standalone machines communicating over the PPP link (if they have existing IP addresses)
Two network endpoints communicating over the PPP link
Remote host connecting to a network dial-in server through a point-to-point link
Dial-in server connecting to remote hosts through a dynamically allocated point-to-point link
When you edit the /etc/inet/hosts file on a local endpoint, supply the IP address of its primary network interface and host name and the IP address of the peer host on the other end of the link.
In this method, you assign a unique host name and IP address to the PPP network interface. (You might want to call the interface hostname-ppp.) Use this addressing scheme fo:
Endpoint machines on a network used as a multipoint dial-in server
Machines on a virtual network
Remote host that uses a dedicated IP address for communicating with a dial-in server over a dynamically allocated PPP link. (Note that this is not a requirement for the dynamic link configuration.)
Machine that is also configured as a router for a physical network, such as Ethernet or Token Ring
Machine in a standalone-to-standalone configuration that does not have an existing IP address. (The PPP interface becomes the primary network interface.)
You must specify the unique address and host name for the PPP network interface in the asppp.cf configuration file.
To create the new host name and IP address, add it to the /etc/inet/hosts file on the endpoint machines, as described in "hosts Database".
You create a new network number for the PPP configuration when it involves:
Virtual networks of computers communicating through PPP multipoint links (required)
A multipoint dial-in server and its remote hosts (required)
The PPP link between two networks, particularly when one or both of the network endpoint machines are also routers for a physical network (optional)
(See Chapter 3, Planning Your Network, for information on network numbers.)
The PPP link becomes a virtual network, since it does not involve any physical network media. You need to type its network number in the networks database on all endpoint machines, along with the network numbers of the networks being linked.
Example 8-1 shows a sample /etc/inet/networks file for an internetwork with PPP:
kalahari 192.9.253 negev 192.9.201 nubian-ppp 192.29.15 |
In the sample file, kalahari and negev are two local area networks, and nubian-ppp is the name of the PPP link.