Not that I've ever experienced. The provider may block it, but IME that's as easy as sending them an email to open the port (which I would consider under the u

Not that I've ever experienced. The provider may block it, but IME that's as easy as sending them an email to open the port (which I would consider under the umbrella of "decent internet"). I can't say I've ever had my IP blacklisted that I know of, and I've never had delivery problems.