> Most application protocols work just fine behind NAT. FTP works with > an ugly work-around. The main protocol that breaks down is SIP. > there are a couple of problems with this analysis: one is that it considers only application protocols that are in widespread use. there are lots of applications that are used by limited communities that are nevertheless important. and of course, since NATs are so pervasive, most of the applications that are in widespread use have been made to work with NAT (often at tremendous expense, and reduced reliability). another problem is that it only considers current applications. a big part of the problem with NAT is that it inhibits the development/deployment of useful new applications. Keith _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf