[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Multihoming an end user



possibility would be if you controlled your own DNS (and if the clients connected by name instead of IP), you could have the same script that monitors your Internet connection take care of changing the DNS entry to point to a secondary IP on the Watchguard (from the secondary ISP's IP block).


> Changing the DNS entries on the fly isn't a workable solution
> because the change won't take affect until all the remote caches
> expire.

Why?

Is it common for remote caches to ignore TTL and negative TTL?

With a tiny (< 100 connections per day) user base, you can pretty comfortably set DNS TTL and negative TTL to 60 seconds, even with caching 3 levels deep, it will take 3 minutes for the right IP# to be used.

This assumes a DNS server at an IP# that is on neither of the two effected blocks...

Also, if as was the case with the OP, ISP1# cuts service off explicitly and deliberately for political reasons, they are also likely to suddenly stop routing.

How would such a cut-off effect the whole ARIN/ASN/BGP/magic-beyond-my-humble-understanding thing?



Reply to: