N900 2.4ghz network drops Internet but 5ghz ok

Do you mean a static IP for all of my devices connecting to the router?

Oh, forgot to add. I returned to my router after being away for the weekend and my devices were working fine. However, after about an hour or two the internet no longer worked on anything connected to the 2.4ghz network. If I restart the router it works fine for 30-60min but then craps out again. The wireless signal still broadcasts and my devices can connect - however I’m unable to access anything, including the router admin page.