CentOS Multiple NIC Configuration

[blueboy2001]

I'm running CentOS 6.5 on a HP Microserver, which has 2 network interfaces.

The box is being set up to be used as a Squid reverse proxy.

The interfaces show in CentOS as eth0 and eth1.

eth0 has an IP of 172.16.2.29/16
eth1 has an IP of 172.16.17.10/16

With eth0 physically connected to the network (eth1 unplugged), the machine responds to ping requests for both IP's.

With eth1 physically connected to the network (eth0 unplugged), the machine fails to respond to pings on either IP.

The above tests are done moving the same cable to the other socket - there's nothing different in terms of switch configuration.

If I do ifconfig eth1 down, it still responds to 172.16.17.10.

When I plug/unplug the cables, I get a message in the console showing this on the relevant interface.

It seems to me that it must be something clever that CentOS is doing because the addresses are on the same subnet, but this is undesirable.

When the box is installed, eth1 will be connected to a separate VLAN containing some web servers we don't want on our network. We want our LAN users to hit the eth0 address and this box to proxy the traffic.

 

[memyselfandi]

What's your output from:

ip addr

 

[blueboy2001]

[root@proxy]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether a0:48:1c:b8:a2:14 brd ff:ff:ff:ff:ff:ff
    inet 172.16.2.29/16 brd 172.16.255.255 scope global eth0
    inet6 fe80::a248:1cff:feb8:a214/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether a0:48:1c:b8:a2:15 brd ff:ff:ff:ff:ff:ff
    inet 172.16.17.10/16 brd 172.16.255.255 scope global eth1
    inet6 fe80::a248:1cff:feb8:a215/64 scope link
       valid_lft forever preferred_lft forever
[root@proxy]#