Redirect all except one specific URL & WP admin

Hi

Your plug-in looks super – but I’m having noob issues – hope you can advise.

>> I am migrating a site from – olddomain.com to newdomain.com
>> I want all attempts to visit any page on olddomain.com to be redirected to newdomain.com – not to pages of newdomain.com
>> I want to be able to access the wp-admin pages without being redirected.

If possible – I would like attempts to go to one specific page say – olddomain.com/entry – also to not be redirected. This is because I am using WP All in one Security to mask the WPAdmin log-in.

Hope my question is clear.

TIA