I have a Linode with Ubuntu 12.04 on it and am having trouble getting a second IP set up as a virtual interface. I've configured the interface as you can see from my /etc/networking/interfaces file here:

# The loopback network interface
auto lo
iface lo inet loopback

# Interfaces brought up durring boot
auto eth0 eth0:0 eth0:1

# eth0 - Public IP, WAN access
iface eth0 inet static
    address 72.14.191.251
    netmask 255.255.255.0
    gateway 72.14.191.1

# eth0:0 - Public IP, WAN access
iface eth0:0 inet static
    address 173.255.199.148
    netmask 255.255.255.0
    gateway 173.255.199.1

# eth0:1 - Private IP, LAN access
iface eth0:1 inet static
    address 192.168.128.46
    netmask 255.255.128.0

The interface in question is eth0:0 with the IP of 173.255.199.148, no connection can be made to that IP. I can't even ping it. If I run ifconfig, all interfaces show as up:

eth0      Link encap:Ethernet  HWaddr f2:3c:91:ae:a0:8b  
          inet addr:72.14.191.251  Bcast:72.14.191.255  Mask:255.255.255.0
          inet6 addr: 2600:3c00::f03c:91ff:feae:a08b/64 Scope:Global
          inet6 addr: fe80::f03c:91ff:feae:a08b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3664 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2908 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:330670 (330.6 KB)  TX bytes:970665 (970.6 KB)
          Interrupt:44 

eth0:0    Link encap:Ethernet  HWaddr f2:3c:91:ae:a0:8b  
          inet addr:173.255.199.148  Bcast:173.255.199.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:44 

eth0:1    Link encap:Ethernet  HWaddr f2:3c:91:ae:a0:8b  
          inet addr:192.168.128.46  Bcast:192.168.255.255  Mask:255.255.128.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:44 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:135 errors:0 dropped:0 overruns:0 frame:0
          TX packets:135 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:141948 (141.9 KB)  TX bytes:141948 (141.9 KB)

Trying to bring the interface down or up doesn't help either:

chris@Optimus:~$ sudo ifdown eth0:0
ifdown: interface eth0:0 not configured
chris@Optimus:~$ sudo ifup eth0:0
RTNETLINK answers: File exists
Failed to bring up eth0:0.

Nor does restarting networking:

chris@Optimus:~$ sudo /etc/init.d/networking restart
 * Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces
 * Reconfiguring network interfaces...                                                                                                                                                                                                         resolvconf: Error: /etc/resolv.conf isn't a symlink, not doing anything.
resolvconf: Error: /etc/resolv.conf isn't a symlink, not doing anything.
resolvconf: Error: /etc/resolv.conf isn't a symlink, not doing anything.
ssh stop/waiting
ssh start/running, process 4289
RTNETLINK answers: File exists
Failed to bring up eth0:0.
resolvconf: Error: /etc/resolv.conf isn't a symlink, not doing anything.
ssh stop/waiting
ssh start/running, process 4361

Even a complete system reboot did nothing. What is the problem here? What am I missing?

Hello,

Both are pinging for me from here. Still having a problem?

-Chris

Thanks caker. Not sure what happened. Rebooted server one last time and it seems to be working now. I'm really confused, but at least it's working.

Rebooting is required after adding a new IP for Linode to route things to your box.

The part that confuses me is that I rebooted the server probably a dozen times in an attempt to debug the problem. It wasn't until after the last reboot that things started working. My only guess is that the IP change took a while to propogate on Linode's backend thus preventing it from working at first.