What kind of paint can I use to paint the front door? It's a steel

Boy, I hate to hear that. The only thing that will work and not peel is oil paint. Unfortunately you're going to have to sand or use a gel paint remover to get all the old paint off down to the bare metal. I take off the doors and work on them flat. It's so much easier. Once all the paint is off use any outdoor hole filler to fill any dents and dings (personally I use car dent putty which is a two part epoxy). Sand lightly and paint with an oil paint. It will last for years no matter the weather.

Junk Monkey says theirs will stay on anything! Look it up and see

Check your local shop for price, their paint is the best, .I have heard if you take it to a car shop they will paint it for you.

I've never had an issue with tremclad, it's made especially for metal, it will paint over rust, you can buy it in a spray can, or tin and brush or roller it on.

Oil based paint! But I'd take a photo to Home Depot and also get an in person rec.

I can't tell you what will work, but I can tell you that hammered finish Rustoleum has not worked for me. It bubbles within a year, I scrape and repaint it, and on and on.

Benjamin Moore has a steel door paint. it is good, not great, but it does lasts,

not great because of the care it needs to apply.

As Bijous, said in reply you will have to remove all old paint. that is correct and that you are better to take door off and lay flat to paint.

The Benjamin Moore needs at least 2 coats, no matter what they tell you, and drying time is 24 - 48 hours (depending on temperature) then light sanding again, and add a second coat.

use only the premium paint brushes / rollers for use with B.M. paint, it will leave stroke marks if not applied correctly.

sorry for your trouble with this door. I had similar problem years ago and leant from that. Good Luck and good sanding..