6.PPP接続 (pppd編)
mgetty側の設定 login.config
 /AutoPPP/ -    -       /usr/sbin/pppd
pppdの設定(1) /etc/ppp/options
 -detach
 lock
 modem
 crtscts
 115200
 /dev/cuaa2
 auth +pap login
 proxyarp
 192.168.1.254:192.168.1.252
pppdの設定 (2) /etc/ppp/(chap|pap)-secrets
 # client        server  secret                  IP addresses
 mira    *       ""      *