I have two NICs.. one (eth1) of which is doing nothing currently (will be for LAN) and the other (eth0) is connected to my DSL modem (ppp0). I'm using Redhat9.0, and when the network starts it brings up eth1 and ppp0 (and lo) usually without problems (sometimes ppp0 doesn't activate unless I do it manually). eth0 never activates.. in fact I've stopped it from automatically activating at boot since it never does anyway.
But how can my ppp0 activate, and I can connect to the internet without any problems but eth0 doesn't activate? If these are two separate logical devices on my PC (using the same hardware), then should I assign an address to eth0 as I do currently with eth1? Let me know a printout of some files will help.

show us the output of these commands...

ifconfig -a
cat /etc/modules.conf
cat /etc/sysconfig/network-scripts/ifcfg-eth0
cat /etc/sysconfig/network-scripts/ifcfg-ppp0

what kind of nic is it? Type of modem?

Here is the info that you ask for and a little more in case it can help.

Here's what I got:
-linux PC with two NICs; eth0 connected to DSL modem and eth1 connected to LAN
-I am assuming my default route needs to be ppp0 (correct me if wrong)
-my eth0 is never activated with current setup, is this because I don't assign it an IP address?
-let me know if you see anything that doesn't look right with the below info... thanks.

/etc/hosts:
# Do not remove the following line, or various programs
# that require network functionality will fail.
#local info:
127.0.0.1 localhost.localdomain localhost #loopback
192.168.1.1 linux.joshuapurcell linux #eth1
#LAN info:
192.168.1.2 boss.joshuapurcell boss #main PC
192.168.1.3 lt.joshuapurcell lt #laptop
---------------------------------------------------------------------------------------
/etc/sysconfig/network:
NETWORKING=yes
HOSTNAME=linux.joshuapurcell
FORWARD_IPV4=yes
GATEWAY=192.168.1.1
GATEWAYDEV=eth0
---------------------------------------------------------------------------------------
/etc/sysconfig/network-scripts/ifcfg-eth0:
DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
USERCTL=no
PEERDNS=no
TYPE=Ethernet
---------------------------------------------------------------------------------------
/etc/sysconfig/network-scripts/ifcfg-eth1:
DEVICE=eth1
BOOTPROTO=none
ONBOOT=yes
USERCTL=no
PEERDNS=yes
TYPE=Ethernet
IPADDR=192.168.1.1
NETMASK=255.255.255.0
NETWORK=192.168.1.0
BROADCAST=192.168.1.255
---------------------------------------------------------------------------------------
/etc/sysconfig/network-scripts/ifcfg-pp0:
# Please read /usr/share/doc/initscripts-*/sysconfig.txt
# for the documentation of these parameters.
USERCTL=yes
PEERDNS=yes
TYPE=xDSL
DEVICE=ppp0
BOOTPROTO=dialup
ONBOOT=yes
PIDFILE=/var/run/pppoe-adsl.pid
FIREWALL=NONE
PING=.
PPPOE_TIMEOUT=80
LCP_FAILURE=3
LCP_INTERVAL=20
CLAMPMSS=1412
CONNECT_POLL=6
CONNECT_TIMEOUT=60
PERSIST=yes
SYNCHRONOUS=no
DEFROUTE=yes
USER=bobleroy
PROVIDER=Advantex
ETH=eth0
---------------------------------------------------------------------------------------
route table:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
info1.masterlin * 255.255.255.255 UH 0 0 0 ppp0
192.168.1.0 * 255.255.255.0 U 0 0 0 eth1
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
127.0.0.0 * 255.0.0.0 U 0 0 0 lo
default info1.masterlin 0.0.0.0 UG 0 0 0 ppp0
---------------------------------------------------------------------------------------
/etc/modules.conf:
alias eth0 8139too
alias eth1 tulip
alias usb-controller usb-uhci
alias sound-slot-0 i810_audio
post-install sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -L >/dev/null 2>&1 || :
pre-remove sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -S >/dev/null 2>&1 || :
---------------------------------------------------------------------------------------
ifconfig -a:
eth0 Link encap:Ethernet HWaddr 00:10:B5:6F:FA:99
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:112536 errors:0 dropped:0 overruns:0 frame:0
TX packets:116621 errors:0 dropped:0 overruns:0 carrier:0
collisions:39 txqueuelen:100
RX bytes:64732311 (61.7 Mb) TX bytes:13616717 (12.9 Mb)
Interrupt:5 Base address:0xa000

eth1 Link encap:Ethernet HWaddr 00:C0:F0:3F:39:06
inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1816 errors:1 dropped:0 overruns:0 frame:0
TX packets:1089 errors:19 dropped:0 overruns:0 carrier:38
collisions:0 txqueuelen:100
RX bytes:180329 (176.1 Kb) TX bytes:107256 (104.7 Kb)
Interrupt:3 Base address:0x400

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:320 errors:0 dropped:0 overruns:0 frame:0
TX packets:320 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:28455 (27.7 Kb) TX bytes:28455 (27.7 Kb)

ppp0 Link encap:Point-to-Point Protocol
inet addr:66.228.158.70 P-t-P:66.228.128.7 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1492 Metric:1
RX packets:3858 errors:0 dropped:0 overruns:0 frame:0
TX packets:4237 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:2947863 (2.8 Mb) TX bytes:536462 (523.8 Kb)

It seems that eth0 is configured and working. It does not have an ip address, is that what your refering to?

I don't think it needs one because the routing table is not using eth0, it is using ppp0.

eth0 is setup to activae on boot. I would change it in the ifcfg-eth0 file

ONBOOT=no


see if your ppp0 script is bringing up eth0

If ppp0 is not coming up on boot then you might want to look in /var/log/messages after bootup for errors and post them.