NET. PPPoE. Пример настройки для Gentoo.

Образец сетевых настроек при ADSL подключении.

Описан полный файл /etc/conf.d/net.
############################# /etc/conf.d/net ### begin ###
# This blank configuration will automatically use DHCP for any net.*
# scripts in /etc/init.d.  To create a more complete configuration,
# please review /etc/conf.d/net.example and save your configuration
# in /etc/conf.d/net (this file :]!).

# eth0 = iface на ADSL
#config_eth0=( "null" )
# если настройки сети не нужны
config_eth0=( "192.168.1.2/24" "192.168.0.2/24" )
# если настройки сети нужны

# eth1 = iface на Lan
config_eth1=( "192.168.100.1 netmask 255.255.255.0" )

# PPPoE config
config_ppp0=( "ppp" )
link_ppp0="eth0"
plugins_ppp0=( "pppoe" )

username_ppp0='username' # user name for connect
password_ppp0='password' # passwd for connect

pppd_ppp0=(
"noauth"         #noauth - Don't ask your ISP to authenticate itself to you. Because it won't.
"defaultroute"         #defaultroute - pppd will automatically add a default route (i.e. your ISP's gateway)
#"nousepeerdns"     #usepeerdns - will get and use up to two DNS server addresses from your ISP.
"default-asyncmap"     #escape all control characters #избежать всех управляющих символов
"ipcp-accept-remote"     #Accept whatever the ISP tells you its IP address is
"ipcp-accept-local"    #Accept whatever the ISP thinks your IP address is
#"holdoff 10"        #podoghdat 10 sec pered perepodkl
#"child-timeout 60"    #???
"lcp-echo-interval 5"     #request that the ISP send an LCP-ECHO packet every 5 seconds
"lcp-echo-failure 3"     #consider the link dead if 3 consecutive requests go unanswered
"mru 1492"
"mtu 1492"
"debug"         #print connection info to the system logs
)

#Depend on eth0 and eth1 as they may require extra configuration
depend_ppp0() {
  need net.eth0
}
############################# /etc/conf.d/net ### end ###
В контексте данной информации рекомендую ознакомиться с inetcheck.sh