Re: mh (RE: OMB: IPv6 by June 2008)

["Steven M. Bellovin" <smb () cs columbia edu>]

In message <20050707195433.3B5EC1862 () testbed9 merit edu>, "Tony Hain" writes:
> Mangling the header did not prevent the worms, lack of state did that. A
> stateful filter that doesn't need to mangle the packet header is frequently
> called a firewall (yes some firewalls still do, but that is by choice). 

Absolutely correct.  Real firewalls pass inbound traffic because a 
state table entry exists.  NATs do the same thing, with nasty 
side-effects.  There is no added security from the header-mangling.

                --Steven M. Bellovin, http://www.cs.columbia.edu/~smb