Moving sites to new ips

What impact would that have on the rankings

[Katz]

I have a very old server and am planning to move my sites to a new server which comes with new ips.

How much time would the SEs need to catch my new ips.
What impact would that have on my rankings

Would it be better to copy them to the new server, change the DNS and
1: leave a backup on the old ips for a month.
2: set a permanent redirect on the old ips to the new ips

[Robert Charlton]

Would it be better...

Katz - Welcome to WebmasterWorld.

"1" is the way to go. Have the site up on both servers, change the DNS, and it will all happen in 3 days or so.

I don't understand "2." If you're keeping the same domain name, and the sites are the same, there's nothing to redirect. If you're changing the sites, I'd move to the new IP# first and then do your changes.

Here's a diary of a site move I just did where there was a last minute change in plans....

Emergency situation in changing hosts
Host says it can't point DNS outside its own system
[webmasterworld.com...]

Learning curve about some DNS concepts was a little steep for me, but the move was much easier than I anticipated and went without a glitch. If you're running your own server, you're already way ahead of where I was.

[Katz]

Thanks Robert

I have no problems with the DNS nor the host as they are mine.

I just thought that once the SEs find that widgets.com resolves to 111.111.111.111 they keep crawling 111.111.111.111
And setting a redirect from 111.111.111.111 to 222.222.222.222 will let them know sooner that the latter is the new ip of widgets.com.

While just leaving a copy at 111.111.111.111 will encourage them to crawl the wrong ip for a long time.

That is what I'd like to know - how often do the SEs update their host-to-ip dbase

Thanks again

[MrSpeed]

Do spiders go by IP or domain name? I always assumed it was domain name due to virtual hosting where many sites share the same IP.

[Robert Charlton]

Katz - I had originally thought, as I think you are thinking, that it might be best to repoint the DNS at the first host to the webserver at the second host. This isn't "redirecting" as I think of redirecting, but I guess it might be called "repointing." I concluded, after observing the migration and thinking about the above, that it wouldn't have made any difference.

Keep in mind that queries for a site are generally for the name, not the IP#, and the DNS then sends those name-based queries to the right IP.

In the thread I reference above, I conclude that, during the transition, the engines, or users, will only see one IP or another. Whatever site they see, it will be the same. Eventually, as the address of the new authoritative DNS (as specified at the registrar level) progagates, the network will shift over to the new DNS.

You are leaving the old site up for queries that haven't yet seen the updated DNS. Once Google sees the authoritative new DNS, as specified by the registrar, they should stop crawling the old one. The propagation period is for the propagation of the authoritative DNS address and the refreshing of caches.

Re cached DNS, I say...

As I've been thinking through the whole process, I'm not understanding the concern I've frequently seen expressed on the board about possible dupe content penalties if Google looks at an old DNS cache. Since Google's index is name based, I'm assuming Google will see one site or the other and think they're the same, not dupes. Anything I'm not getting here?

I'm a relative beginner in this subject, but I'd suggest you reread the thread, which has some good posts about how DNS works.