Google optimization - two domain names to one site

[wilku]

Hi
I have a question regarding Google. I have one site (let's say www.mysite.pl) which is indexed in google. I have added a sitemap in xml using Google tools for webmasters. And now I have another domain name (let it be keyword.domainname.pl) It is a simple redirection with masking - url shows keyword.domainname.pl all the time but all links on a page are www.mysite.pl based. I can change it if it's a problem.
How to tell Google to index this one as well (as you see there is a keyword I'm targeting in the second name)? Is it good practice to have two domain names for one site?
Thank you for any thoughts on this.

[callygull]

Re-directing is never a good practice for Google. Google sees this as way to spam more keywords in different locations for only one web site. If you are attempting to rank well in Google, I would stop this practice immediately. http://www.internetofficer.com/seo/302-redirect/
http://www.seochat.com/seo-tools/redirect-check/
Here are a couple of places you should check out.

Callygull
edited by admin: no commercial links permitted on the forum, thank you

[wilku]

Thank you for your answer. I'll change it then. Would permanent redirection be ok?

[MarkR]

Permanent redirection is fine, Google will index the page only once and count any links to the redirects as if they were links directly to the target page.

Google should not treat such pages as spam, rather just permanent redirects. Use a permanent redirect if possible. Don't use: meta-refresh, refresh-header, javascript or other techniques.

Mark