Debian/OVH: How to configure multiple Failover IP on the same Xen (Debian) Virtual Machine?

Posted by D.S. on Server Fault See other posts from Server Fault or by D.S.
Published on 2012-08-28T16:48:27Z Indexed on 2012/09/01 9:40 UTC
Read the original article Hit count: 411

Filed under:
|
|
|

I have a problem on a Xen virtual machine (running latest Debian), when I try to configure a second failover IP address. OVH reports that my IP is misconfigured and they complaint they receive a massive quantity of ARP packets from this IPs, so they are going to block my IP unless I fix this issue.

I suspect there's a routing issue, but I don't know (and can't find any useful info on the provider's website, and their support doesn't provide me a valid solution, just bounce me to their online - useless - guides).

My /etc/network/interfaces look like this:

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
    address AAA.AAA.AAA.AAA
    netmask 255.255.255.255
    broadcast AAA.AAA.AAA.AAA
    post-up route add 000.000.000.254 dev eth0
    post-up route add default default gw 000.000.000.254 dev eth0

# Secondary NIC
auto eth0:0
iface eth0:0 inet static
    address BBB.BBB.BBB.BBB
    netmask 255.255.255.255
    broadcast BBB.BBB.BBB.BBB

And the routing table is:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
000.000.000.254 0.0.0.0         255.255.255.255 UH    0      0        0 eth0
0.0.0.0         000.000.000.254 0.0.0.0         UG    0      0        0 eth0

In these examples (true IP addresses are replaced by fake ones, guess why :)), 000.000.000.000 is my main server's IP address (dom0), 000.000.000.254 is the default gateway OVH recommends, AAA.AAA.AAA.AAA is the first IP Failover and BBB.BBB.BBB.BBB is the second one.

I need both AAA.AAA.AAA.AAA and BBB.BBB.BBB.BBB to be publicly reachable from Internet and point to my domU, and to be able to access Internet from inside the virtual machine (domU). I am using eth0 and eth0:0 because due to OVH support, I have to assign both IPs to the same MAC address and then create a virtual eth0:0 interface for the second IP.

Any suggestion? What am I doing wrong? How can I stop OVH complaining about ARP flood?

Many thanks in advance, DS

© Server Fault or respective owner

Related posts about networking

Related posts about ip