Installing and Administering PPP

Chapter 4 83
Common pppd Options
IP Routing Tips
ARP Table Manipulation. If a separate subnet number is
unavailable for use by remote-access machines, it is possible to assign
the remote machines addresses on the same subnet number as the
departmental LAN. As above, suppose the organization’s class B network
number is 134.19, and they are subnetting with a class C-sized network
mask of 0xffffff00. The departmental LAN is subnet 134.19.5.0,
populated by hosts alpha (134.19.5.22) and bravo (134.19.5.41). A modem
is attached to one of alpha’s serial ports, and alpha’s Login shell script is
the generic one described above. A laptop named nomad wishes to
connect to the network.
Assign nomad the IP address 134.19.5.114. The PPP daemon on nomad
would be started in the Autostart script as
pppd 134.19.5.114:134.19.5.22 auto idle 180
or, if all the names can be found in the local /etc/hosts:
pppd nomad:alpha auto idle 180
The next line in nomad’s Autostart would set up an IP route through
the dial-in gateway:
route add net 134.19.0.0 134.19.5.22 1
Figure 4-2
Alternatively, and necessarily if the LAN were also connected to the
Internet:
route add default alpha 1
Similarly, the pppd on alpha would be started as:
pppd alpha:nomad auto idle 180
Alpha would run the following command at boot time: