On 8/24/07, Chris Boyd <cboyd at gizmopartners.com> wrote: > > On Aug 23, 2007, at 10:30 PM, Feizhou wrote: > > Keep or setup a box inhouse to show the message, when the servers > > are online in the data center, switch ips for the names over and > > then change the setup on the box to either redirect or proxy the > > requests to the real servers to handle incoming http requests due > > to cached dns entries. > > Also, lower the cache time in your nameserver's zone files so that > people will see the new IP addresses faster. 3600 seconds works > pretty well, but I've used as little as 120 seconds for sites that > are more popular. > > --Chris Messing with DNS is really the wrong way to go on this. You'd be forcing all of the DNS servers involved to start messing with their caches, update more frequently, etc.., pushing the problem out onto "everyone else", and you have no control over any of it really. Cache time is only a suggestion, and not all DNS servers follow it. The way to go is to assign that same IP address to another box during maintenance, and have that box show the page. Then you have full control over when the switch happens. The only potential issue there is ARP caching on your local network.