Redirection of domains

[stevew]

Can anyone help with two related questions relating to redirection of unwanted domains?

1) A new client has a set of interlinked "doorway domains" that have good rankings in themselves, and point to the main domain.
Yes -- total spam.
Some of these domains may be useful as sub-domains in the future so I don't want to wipe them all out.
I understand that I can place a 301 "Moved Permanently" redirect on the domains that I don't want, and a 302 "Object moved" redirect on those that I may want to use later.
Is the 302 redirect SE-friendly, and will it enable me to re-activate a domain if we want to use it as a specialist sub-domain later on?

2) An existing client has listings on two domains, both of which point to the same web space.
I want to focus the effort on a single domain as a matter of good practice, and will be asking sites that link to the website to change the URL.
Is it okay to let the old domain to "die out" in this way, or is there a danger of the site being penalised -- in which case I should point the old domain to another web space with a 301 redirect on it.

[Advisor]

In answer to number one, I believe that anything you do today is only in effect for today. You can change your .htaccess file at any time and your redirects will change accordingly. Once the search engines respider, they should get the new info. (I have no experience with this, it just makes sense to me.)

Regarding number 2, I don't quite understand what you're asking. What do you mean by let the old domain die out?

I would just point both domains to the same IP (park them) and then not worry about it. (And/or put the permanent redirect on the old one to the new one.)

Jill

[stevew]

Thanks, Jill, for your response.

In number 1, as far as I understand, a 301 redirect will mean the SE will flag the domain as "permanently moved" so it will be very difficult to get re-indexed if we want to re-activate it. Whereas a 302 redirect will just mark it as a (perhaps temporary) move. My concern, because of talk about SE opposition to redirects, is that are these techniques acceptable?

In number 2, by letting the old domain die out, I mean that by re-directing links from other sites to the new url, the old domain name will "die out" of its own accord, as incoming links will disappear.
But if the client has reasonably good listings for both URL's, even though they both point to the same web space, is there a risk of a penalty?

[Advisor]

But if the client has reasonably good listings for both URL's, even though they both point to the same web space, is there a risk of a penalty? There's never a penalty for one site that has two domain names. It's treated as the one site that it is.

[stevew]

Thanks for your reply : I'd hoped that was the case.