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

["George Bonser" <gbonser () seven com>]

> Well have the hosts update their own addresses in the DNS.  That's
> one of the problems addressed.  There are at least two commercial
> OSs which will do this for you.
>
> Mark

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.