Hi folks,
I have a server at Soyoustart.com (which is a brand of OVH). I run
CentOS 6.7 and have problems with network configuration.
I want to add a second public ip (failover ip) to the server and did
follow the instructions in the CentOS-section of
http://hilfe.ovh.de/AdministrationIpAliasHinzufuegen
After executing the required steps I'm not able to reach the host via
the second ip from an external host. I tried it with ping and with ssh
commands.
Here the content of the config files (I anonymized the server ip with
xx.xx.xx.xx and the failover ip with yy.yy.yy.yy):
$ cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=<name-of-my-host>
NOZEROCONF=true
GATEWAY=xx.xx.xx.254
$ cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
IPADDR=xx.xx.xx.xx
NETMASK=255.255.255.0
ONBOOT=yes
GATEWAY=xx.xx.xx.254
$ cat /etc/sysconfig/network-scripts/ifcfg-eth0:0
DEVICE=eth0:0
BOOTPROTO=static
IPADDR=yy.yy.yy.yy
NETMASK=255.255.255.255
ONBOOT=yes
When I restart the network I get a message (two times) saying "RTNETLINK
answers: Operation not supported".
$ service network restart
Schnittstelle eth0 beenden: [ OK ]
Loopback-Schnittstelle beenden: [ OK ]
Loopback-Schnittstelle hochfahren: [ OK ]
Schnittstelle eth0 hochfahren: Determining if ip address xx.xx.xx.xx is
already in use for device eth0...
RTNETLINK answers: Operation not supported
RTNETLINK answers: Operation not supported
[ OK ]
I can see two interfaces eth0 and eth0:0
$ LANG="" ifconfig
eth0 Link encap:Ethernet HWaddr ..:..:..:..:..:..
inet addr:xx.xx.xx.xx Bcast:xx.xx.xx.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:11122 errors:0 dropped:0 overruns:0 frame:0
TX packets:14371 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1362900 (1.2 MiB) TX bytes:3462327 (3.3 MiB)
Interrupt:20 Memory:fe500000-fe520000
eth0:0 Link encap:Ethernet HWaddr ..:..:..:..:..:..
inet addr:yy.yy.yy.yy Bcast:yy.yy.yy.yy Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:20 Memory:fe500000-fe520000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:3096 errors:0 dropped:0 overruns:0 frame:0
TX packets:3096 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:274948 (268.5 KiB) TX bytes:274948 (268.5 KiB)
I'm able to reach the host from another host (outside OVH network) via
xx.xx.xx.xx (I use ping and ssh), but not via yy.yy.yy.yy.
Just to be sure that there isn't an issue with the firewall I did
"service iptables stop" and ran the "ping" and "ssh" commands again with
the same result. For ip xx.xx.xx.xx it works, but not for yy.yy.yy.yy.
Not sure if this is important, just in case it matters, some additional
information:
IPv6 is disabled by kernel parameter "ipv6.disable=1" in /etc/grub.conf
The two mac addresses I see for eth0 and eth0:0 with the "ifconfig"
command are the same. In the OVH/Soyoustart.com GUI I created a virtual
mac for the failover ip, I'm not sure if that virtual mac should come
into play somewhere?
$ uname -a
Linux <name-of-my-host> 2.6.32-573.12.1.el6.x86_64 #1 SMP Tue Dec 15
21:19:08 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
$ LANG="" route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
xx.xx.xx.0 * 255.255.255.0 U 0 0 0 eth0
default vss-gw-6k.fr.eu 0.0.0.0 UG 0 0 0 eth0
Why is yy.yy.yy.yy not reachable from outside? What am I doing wrong or
what can I do to narrow down the problem?
Regards,
Meikel
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