Debian/OVH: How to configure multiple Failover IP on the same Xen (Debian) Virtual Machine?
- by D.S.
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
