On Thu, May 2, 2013 at 12:31 PM, Michael Mol mikemol@gmail.com wrote:
with its default gateway pointing toward the ISP handling it. DNS
service is simple enough to have standalone servers for each instance you need.
This would also require either resources or underlying authorizations I don't have.
CentOS VMs are really, really cheap....
Web browsers are actually very good at handling multiple IPs in DNS responses and doing their own failover if some of the IPs don't respond.
It varies greatly by client software. And given the explosion of unreliable network connections (wifi, mobile), some of that failover logic's margin is already lost in dropped packets between the client and their local network gateway.
Yes, but typically they can deal with receiving multple IPs from the initial DNS lookup even if some are broken better/faster than getting one IP which subsequently breaks and then having to do another DNS lookup to get a working target. At least the few broswers I tested a while back did...
For other services you might need to actively change DNS to drop IPs if you know they have become unreachable, though.
Yup. That's what I was planning on doing, more or less. Start with ordering IPs by route preference, drop IPs by link state. I just wish I could drive it by snooping OSPF...
I don't think you can count on your ordering reaching the clients or meaning anything to them if it does. And some applications won't ever do a lookup again.
-- Les Mikesell lesmikesell@gmail.com