I presume they mean pointing their cloudflare tunnel to direct lemmy.example.com to http://localhost/:[port], and I don’t think there’s any special rules about that port from cloudflares site.
I use tunnels and ports in about that range for all my sites, and don’t have any problems.
Yeah, I feel like we’re missing some info here.
I have to admit that I have no experience with yuno. Always seemed interesting, but not like something that fits into my work flow.
If they’re self-hosting at home (which I’m also doing for some services), I’d presume they’re probably running their stuff on a single machine, so I’m not sure where their router would come Into it. The data the cloudflare tunnel process receives should look the same to the router no matter the port it is ultimately sent to, and when it is sent to an address internal to the machine, shouldn’t pass through the router again.