Controlling ports used by natd

[Barney Wolff]

On Fri, Dec 12, 2003 at 01:19:34AM -0700, Brett Glass wrote:
> At 12:45 AM 12/12/2003, Barney Wolff wrote:
> 
> >UTSL libpcap/alias_db.c
> 
> I can find no such file in /usr/src/contrib/libpcap. I did find
> one in /usr/src/lib/libalias. It seems to have in it a function
> called FindNewPortGroup that hunts for ports at random, but
> there's no discipline there to make it avoid specific ports
> or groups of ports. Are you suggesting that I modify this
> function to add port exclusion as a new feature? I suppose that
> I could do this, but it would involve changing data structures
> that were used by many programs, including natd and ppp. So,
> there could be a huge ripple effect.

Oops, sorry for the confusion.  How fancy a change is up to you,
but changing ALIAS_PORT_BASE and ALIAS_PORT_MASK (and _EVEN)
would let you confine the port range without much work.  Un-nat'd
folks are most likely using ports in the hi range, and usually
without trouble - presumably normal programs don't make special
checks for trojan ports.

-- 
Barney Wolff         http://www.databus.com/bwresume.pdf
I'm available by contract or FT, in the NYC metro area or via the 'Net.