1. Prevent protocols to cross layer boundaries. FTP, SIP, etc. are application protocols, yet they use ports and IP addresses for identification of endpoints. T

1. Prevent protocols to cross layer boundaries. FTP, SIP, etc. are application protocols, yet they use ports and IP addresses for identification of endpoints. They break if the transport layer does something they did not anticipate (e.g. NAT). NAT is not evil, nor broken. Protocols not respecting layer boundaries are broken. 2. Make use of DNS SRV records for all services. Why HTTP must be on port 80? Why not consult DNS to resolve the port too? Pretty much related to my first point.