Two Inferfaces one netmask

[Stkcode]

Hello all,

I have a bit of a networking problem. One ethernet card appears to be routing to the second lan card. I have 3 ethernet cards, two for the internet and one for the lan.

They are setup as the following:

Eth0 – 67.115.71.218/255.255.255.248
Eth1 – 67.115.71.221/255.255.255.248
Eth2 – 192.168.1.100/255.255.255.0

I’ve done an “ifconfig” and “lspci” and everything is setup correctly.
Whenever I call 67.115.71.218 (eth0), I’m getting routed to 67.115.71.221 (eth1).

I believe my problem lies in the Kernel IP routing table.
When I do a “route –n”, I get the following:


Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
67.115.71.216 0.0.0.0 255.255.255.248 U 0 0 0 eth1
67.115.71.216 0.0.0.0 255.255.255.248 U 0 0 0 eth1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 67.115.71.217 0.0.0.0 UG 0 0 0 eth0


This is obviously wrong. An “ip route show” displays:

67.115.71.216/29 dev eth1 scope link
67.115.71.216/29 dev eth1 proto kernel scope link src 67.115.71.221
192.168.1.0/24 dev eth2 scope link
127.0.0.0/8 dev lo scope link
default via 67.115.71.217 dev eth0


I can do
route del –net 67.115.71.216 netmask 255.255.255.248 dev eth1

Then a
route add –net 67.115.71.216 netmask 255.255.255.248 dev eth0


“ip route show” now shows:

67.115.71.216/29 dev eth0 scope link
67.115.71.216/29 dev eth1 proto kernel scope link src 67.115.71.221
192.168.1.0/24 dev eth2 scope link
127.0.0.0/8 dev lo scope link
default via 67.115.71.217 dev eth0


And “route –n” now shows

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
67.115.71.216 0.0.0.0 255.255.255.248 U 0 0 0 eth0
67.115.71.216 0.0.0.0 255.255.255.248 U 0 0 0 eth1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 67.115.71.217 0.0.0.0 UG 0 0 0 eth0


Still doesn’t set things right…still goes to the second interface, eth1 (67.115.71.221) when ever I try to go to 67.115.71.218 (first interface, eth0)! Any suggestions?

Any help would greatly be appreciated!

Thanks,
Jon


Additional info:

ifconfig shows this:


eth0 Link encap:Ethernet HWaddr 00:A0:CC:69:70:3D
inet addr:67.115.71.218 Bcast:67.115.71.223 Mask:255.255.255.248
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:991 errors:0 dropped:0 overruns:0 frame:0
TX packets:25 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:59956 (58.5 Kb) TX bytes:2062 (2.0 Kb)
Interrupt:11 Base address:0x4000

eth1 Link encap:Ethernet HWaddr 00:05:5D:CE:A3:E0
inet addr:67.115.71.221 Bcast:67.115.71.223 Mask:255.255.255.248
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:981 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:58922 (57.5 Kb) TX bytes:540 (540.0 b)
Interrupt:10 Base address:0xb000

eth2 Link encap:Ethernet HWaddr 00:05:5D:CE:64:35
inet addr:192.168.1.100 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:295176 errors:0 dropped:0 overruns:0 frame:0
TX packets:223330 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:204328601 (194.8 Mb) TX bytes:118830662 (113.3 Mb)
Interrupt:12 Base address:0xb000

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:18 errors:0 dropped:0 overruns:0 frame:0
TX packets:18 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:948 (948.0 b) TX bytes:948 (948.0 b)

 

[netnew]

Hi there, I also encounter that configuration before where I used PRoxy ARP, to configure my firewall composed of 3 LAN CARDS,; eth0, eth1 eth2 running Linux RH 7.1

eth0 and eth1 uses public IP, and eth2 uses private IP for LAN

IP Configuration
eth0 IP address : 192.168.1.5
Subnet Mask : 255.255.255.128
gateway : 192.168.1.1
eth1 IP Address : 192.168.1.5
Subnet Mask : 192.168.1.5
gateway : 192.168.1.1

eth0 IP address : 192.168.2.1
subnet mask : 255.255.255.0
gateway : 192.168.2.


You have to enable Proxy Arp by adding the foolowing lines to /etc/rc.d/rc.local file.

# SETUP FOR PROXY ARP FIREWALL

echo "1" > /proc/sys/net/ipv4/conf/eth0/proxy_arp
echo "1" > /proc/sys/net/ipv4/conf/eth1/proxy_arp

I think I can't explain this to you well so please check the links below. for more details on Proxy Arp

http://www.sjdjweis.com/linux/proxyarp/

http://www.thelinuxreview.com/howto/IP-MASQ/x122.htm