man pppoectl ..
SYNOPSIS
ispppcontrol [-v] ifname [parameter[=value]] [...]
pppoectl -e ethernet-ifname [-s service-name] [-a
access-concentrator-name] ifname
#!/bin/sh
# Need ethernet interface UP (or it won't send any packets)
ifconfig rtk0 up mtu 1500
# Create a pseudo device
ifconfig pppoe0 create # Let pppoe0 use rtk0 as it's ethernet interface
pppoectl -e rtk0 pppoe0
# Configure authentication
pppoectl pppoe0 \
myauthproto=pap \
myauthname=???? \
myauthsecret=???? \
hisauthproto=none
# Configure the pppoe0 interface itself. This addresses are magic
# meaning we don't care about either address and let the remote
# ppp choose them.
ifconfig pppoe0 0.0.0.0 0.0.0.1 up mtu 1454
route flush
route add -net default 0.0.0.1 -iface