Automatically login when you return to the site

lo

This isnt really a hacking question, I would have posted at vb.com but forgot my password and cant reset cause my email is down.

I have just moved to a new server and have a problem my members keep getting logged out.

I didnt have this problem on the old host so I am thinking is a server problem not a board problem.

I have fixed it for my self by checking yes to.

"Automatically login when you return to the site? (uses cookies)"

What I want to do is make this default for all members and new member when they register, any ideas on how to do this.

thx.