Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 — Unique local addresses)

Fri Oct 22 02:45:37 UTC 2010

On 10/21/2010 9:32 PM, George Bonser wrote:
>
> But they sometimes don't check to make sure there aren't stale DNS entries for their hostname before they add the new one!  I have run into that problem often.  A machine that has been "bounced" several times recently might have a dozen A records for its hostname in DNS.  I won't mention any names but their initials are MICROSOFT.  For many of our machines, there are load balancers, even in the office data center with hard coded IP addresses for the backend servers.  Dynamic address assignment isn't really an option but works fine for things like user machines in the cubes.  You aren't going to be looking those up by A record anyway. Static assignment by DHCP is possible for the devices that do that, you just have to remember to change it if you change a NIC (or if the interfaces are bound together on the box, such as with linux bonding, the "master" interface of the bond changes for some reason like a failure of the previous master).  Static hard coding of the IP address is actually easier to manage in the colo than DHCP or autoconfiguration.
>

Many of these problems are application/implementation issues. Many 
devices need support for dynamic prefix specifications "hey, my 
destination for the load balancer is $prefix:blah", and some devices 
still need support for just setting their IP with RA (though all my 
servers do it fine).

At this time, there are many situations where static assignment is 
probably the only option. Multiple assignments may not be out of the 
question. However, this is due to the shortage of what IPv6 *could* be. 
We are missing so many support protocols and applications that could 
truly make it far superior to IPv4. Then again, I think SCTP is superior 
to udp/tcp, and I don't think I have a single app using it.

Jack