What protocols (besides FTP) are you referring to? FTP translators are
common enough, and I am not aware of any other user application protocols
that transmit IP addresses.I believe CUSeeMe does. I believe NAT also breaks IPSec and mobile IP.
Maybe I am wrong, though...
AFAIK, CUSeeMe doesn't transmit any addresses at the application level. The
clients display IP addresses to the user, most likely due to the assumption
that most people won't remember them and it helps cut unsolicited CUSeeMe calls.
If the client knows that NAT is occurring, IPsec can take that into account
and encrypt/authenticate its packets accordingly. This is a bad solution,
but I doubt IPsec will become common before IPv6 takes over. I have heard
rumors that IPv6 allocations will not be provider-based, so there will be no
need for NAT.
I'm not familiar enough with Mobile IP to comment on that, other than to say
it's not common yet.
pbd
Stephen Sprunk