Moving to new domain
 

I have two sites and I am combining them into one site on domain1.

I use to have the site on Domain1 then moved the forums to Domain2. When I did this many users were locked out and there were countless issues mostly to do with cookies and user passwords.

Now I am moving the forums back to Domain1 after about a year on Domain2.

What I would like to know is what user impacts in terms of cookies* shortcuts etc do I need to know so I can make the move as painless as possible for them and most importantly what steps do I need to take to minimise any user problems especially for those that are always logged in when they return to my site and find it is now on Domain1 - and they may still have an old cookie from the Domain1 days.

Also I presume that the best thing to do is to have a perm redirect htaccess file on Domain2 after I make the move - is that right?

Thanks for your help!