Bricks, Masonry, Asphalt and Concrete - What type sealer to use around boiler vent pipe?

The vent pipe off my boiler heating system goes directly through my concrete cinderblock foundation straight to the outside of my house. I think it's called a "Direct-Vent system". And then my dryer exhaust pipe also goes straight outside through my concrete foundation. Both of these vent pipes are made of metal I believe and I think they do get hot as well. There is no caulking or sealing either on the inside of the house or the outside of the house for these vents. So I get a cold draft of air coming into the house on the sides of these vents. What SPECIFIC product do I need to use to seal around these vents? I guess I need somethign that can take high heat and also bonds well to concrete to hold the vents in place as well as make it air tight.

I need to run to home depot so if you could let me know specifically what I need that would be very helpful. Thank you!

I'm glad you asked this. I have the same setup with my direct vent heater and i also need to seal it, i ocassionally get water dripping in.

You can buy high temp caulk made for this purpose.