Difficult networking problem

From: ShadowEyez (shadoweyez_at_hotpop.com)
Date: 09/23/04


Date: Wed, 22 Sep 2004 23:50:33 GMT

Odd networking problem with Gentoo Linux 2004.2, 2.6.7, i586, stage3 install
There are 3 network interfaces, a modem (ppp0, on /dev/ttyS4), and two 10
mbit ethernet nics (eth0 and eth1) . They are the same type of nics with
the driver loaded into the kernel (NE-2000 realteks but they have different
layer 2 MAC addresses), and the /etc/conf.d/net file has the lines:
iface_eth0="192.168.1.1 broadcast 192.168.1.31 netmask 255.255.255.224"
iface_eth1="192.168.1.2 broadcast 192.168.1.31 netmask 255.255.255.224"
that I set up, meaning all the ip info is right, problem is I can only get
one of the interfaces to work at the same time!

I can ping each interface (192.168.1.1 and 192.168.1.2) but only one
interface will work at one time. I know the hardware and ip address are
right because when I run
ifconfig eth0 down && ifconfig eth1 up
I can plug a working device into eth1 and it works.
ifconfig eth1 down && ifconfig eth0 up
I plug a working device into eth0 and it works, but when both are up THEY DO
NOT WORK AT THE SAME TIME.
The ppp0 interface (modem) is set to be the default route, and adjusting the
routing table does no good. Output of the route command:
Server # route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
nas1.sr2.sonic. * 255.255.255.255 UH 0 0 0 ppp0
192.168.1.0 * 255.255.255.224 U 0 0 0 eth0
192.168.1.0 * 255.255.255.224 U 0 0 0 eth1
loopback localhost 255.0.0.0 UG 0 0 0 lo
default nas1.sr2.sonic. 0.0.0.0 UG 0 0 0 ppp0
The command ifconfig gives:
Server # ifconfig
eth0 Link encap:Ethernet HWaddr 00:C0:0C:B0:57:11
          inet addr:192.168.1.1 Bcast:192.168.1.31 Mask:255.255.255.224
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:8847 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8294 errors:0 dropped:0 overruns:0 carrier:0
          collisions:3 txqueuelen:1000
          RX bytes:1680159 (1.6 Mb) TX bytes:5589375 (5.3 Mb)
          Interrupt:15 Base address:0xb800

eth1 Link encap:Ethernet HWaddr 00:C0:0C:B0:55:1B
          inet addr:192.168.1.2 Bcast:192.168.1.31 Mask:255.255.255.224
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
          Interrupt:12 Base address:0xb400

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:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

ppp0 Link encap:Point-to-Point Protocol
          inet addr:209.148.104.235 P-t-P:209.204.168.83
Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1514 Metric:1
          RX packets:7830 errors:1 dropped:0 overruns:0 frame:0
          TX packets:8392 errors:0 dropped:12 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:5422514 (5.1 Mb) TX bytes:1408388 (1.3 Mb)
Again, though I can ping the eth1 interface, nothing plugged into it will
work. All cables and cards are plugged in and working. How do I get both
ethernet interfaces working?

TIA
ShadowEyez