[169577] in North American Network Operators' Group
Re: ISP inbound failover without BGP
daemon@ATHENA.MIT.EDU (Sebastian Spies)
Tue Mar 4 09:16:55 2014
Date: Tue, 04 Mar 2014 15:16:19 +0100
From: Sebastian Spies <s+Mailinglisten.nanog@sloc.de>
To: nanog@nanog.org
In-Reply-To: <CAP-guGWg3HWC+5W54rAN0ycX=FfZQt2-B3Kf-8zrXL7dadpboA@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Am 04.03.2014 05:19, schrieb William Herrin:
> Reasons why dynamic DNS fails to perform as expected include:
>
> * Web browser DNS pinning can result in a customer's web browser
> holding the old IP address indefinitely.
>
> * Host-level caching of looked up names which discards the TTL.
> Remember: your desktop or laptop performs lookups against multiple
> name services, e.g. DNS, /etc/hosts, lmhosts, NIS+. DNS TTL is no
> longer in scope once the name to address map enters the generic host
> lookup mechanism. Most OSes have a fixed timeout of one sort or
> another, some old ones as long as 24 hours.
* Eyeball ISPs' DNS resolvers might tamper with TTL values.
-- SEBASTIAN SPIES lnked.in/sspies vastly.de
