Thanks a lot, Sean!
That's what I want.
Cheers,
Ross

"sean dreilinger" <sean-usenet@durak.org> wrote in message
news:46A3A591.8070706@durak.org...
> hi Ross:
>
> Ross wrote:
>> I have a existing Apache web server for my company www.company.com with
>> the IP of 100.100.100.100.
>> Now, I am planning to move it from an ISP to another, so it's IP address
>> has to be changed, and it would be 200.200.200.200.
>> To zero the downtime, I'd like to set up a new server at the new ISP with
>> the new IP, and keep the old server at the current ISP for a while and
>> forward its access to http://200.200.200.200.
>> The question is how to set up the forwarding/redirection on the current
>> Apache, and it won't change the address in the browser's address field?
>
> if i understand what you're asking, success depends as much on what you do
> with your DNS configuration as your apache setup. to switch from ISP.old
> to ISP.new with a minimum of disruption, try this:
>
> 1. reduce the dns refresh time on the company.com zone and ttl on the
> www.company.com resource record to 5 minutes. if your existing ttl/refresh
> is 8 hours, you need to do this at least 8 hours before the move. i would
> do it well in advance so that you don't have to worry about it.
>
> 2. prepare your website at ISP.new and configure apache to recognize and
> accept traffic for www.company.com
>
> 3. once the DNS ttl has propagated (hours or days after you've set it to 5
> minutes), change the IP address of www.company.com in DNS from ISP.old to
> ISP.new. most traffic will switch and start landing at ISP.new within 5
> minutes.
>
> 4. you can now safely assume that traffic arriving at ISP.old is ignoring
> DNS. after examining the nature of the traffic, you can drop it altogether
> (just turn off the old server if the traffic looks like robot noise), or
> if the remaining traffic looks legitimate, you can set the apache at
> ISP.old to redirect any/all traffic to ISP.new. in httpd.conf at ISP.old:
>
> RedirectMatch permanent ^/(.*)$ http://www.company.com/$1
>
> which would hopefully force clients who have cached your IP to do a fresh
> lookup. if you really want to keep all of your bot traffic and whatever
> else is not properly respecting your DNS entry, you can redirect any/all
> traffic to the IP of your machine at ISP.new, like this:
>
> RedirectMatch permanent ^/(.*)$ http://200.200.200.200/$1
>
> i doubt this will net you any human traffic of value, it will just
> increase robot noise on your new server.
>
> 5. restore your dns refresh/ttl to a more reasonable duration, allowing
> clients to cache your zone information for hours or days.
>
> --sean
>
> --
> sean dreilinger - http://durak.org/sean/