Re: Cisco IP phone and NAT

[Daniel Hartmeier <daniel_(_at_)_benzedrine_(_dot_)_cx>]

On Sun, Dec 30, 2001 at 06:26:35PM -0600, Ricardo Londono wrote:

> What is this Selsius Skinny Protocol?  Never heard of it.  I had figured 
> that I just open up certain ports and such but I guess not?  Anyone have 
> any ideas? or has anyone actually done something like this?

The Cisco document you quoted is quite clear. The protocol transmits IP
addresses inside the data stream. A NAT gateway that just changes the
outer addresses but ignores the addresses inside the data will break the
protocol (much like FTP, for instance).

Cisco's IOS NAT has support for this protocol. With OpenBSD as NAT
gateway, you'd need a proxy to deal with changing addresses inside the
data stream, like ftp-proxy does for FTP.

Daniel