Do 6in4/SIT Tunnels run on a specific port?

[helpdeskaleer]

Hello,

I am trying to setup a 6in4 Tunnel on an OpenWRT Router.

I thought that I could put my router on the Xfinity DMZ to get it working, but I was told that it wouldn't work because my Xfinity Router needed to be put in Bridge Mode for it to work.

I scoured various sources for information on Linux SIT Tunnels and what port they use, but I haven't been able to find anything on it.

Is this because it runs on a OSI Layer that doesn't include ports, and makes it require bridge mode?