Solved Adding ipv6 to a Linux Router

floyd

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I have a linux (CentOS 7) router in my cabinet at the data center. It does all the routing for my public ipv4 addresses to the other servers in the cabinet.

I have just been given some ipv6 addresses but I am not sure what to do to get started. I already have an ipv4 assigned to eth0. Can I simply add the ipv6 as an alias like eth0:1 to get started? And how can I have a ipv4 gateway and ipv6 gateway on the same machine?

I hope somebody can help. This is my first attempt at ipv6.
 
Does anybody else use Linux as a router in their data center?
 
Maybe this can help:
 
I appreciate the reply. I am using global ipv6 so I think the configuration may be different.
 
I have ipv6 working on the public facing interface. But I am having trouble forwarding the global ipv6 addresses through the router to the other machines in my cabinet.
 
I think I figured it out. I wish I knew what I was doing wrong before. But this time I did write down what I did correctly.
 
Ok so not quite fixed. From the inside I can ping through the router to the outside 6 times and then it pauses for 27 seconds over and over. What would cause it to be blocked over and over again for 27 seconds.
 
Maybe the DC is blocking overuse of icmp. Maybe ipv6 is new to them to?
 
I have tried it from different machines on the inside and they all ping and pause at the exact same time. And it always pings 5 or 6 times and pauses for 27 seconds.

I have run tcpdump on the router to watch for the traffic. When I run it against the LAN interface I continually see the ping traffic trying to get through. When I run tcpdump on the WAN interface I only see the ping traffic get through when there is successful pings.

Its not just pings. I tried using wget to retrieve a ipv6 web site and same thing happens. Sometimes its successful immediately and sometimes it has to wait until the router allows it.

So something on the router is blocking ipv6 traffic for 27 seconds at a time. I have no idea what that could be. I don't think I have anything special running on it. I have turned off everything I could think of. I turned off the firewall just to check.

I do have in /etc/sysctl.conf and reloaded it:
net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1

Is there a problem with routing ipv4 and ipv6 at the same time?
 
I set up a test lab in my home and everything worked as expected. So there is something wrong with the machine or software running. I am just going to replace it. I would have liked to have solved the problem but at some point I have to call it quits.
 
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