IPFW with user-ppp's NAT

Erik Trulsson ertr1013 at student.uu.se
Sun Mar 16 16:03:21 UTC 2008

On Sun, Mar 16, 2008 at 04:37:18PM +0100, Wojciech Puchar wrote:
>> Frankly I'm a bit surprised that this hasn't been more widely heralded,
>> as userland natd is often given as a reason to prefer other firewalls,
> what's wrong in userland natd?

Performance.  With userland natd, every packet that passes through natd
must pass from kernel to userland (causing one context switch) and back
again (causing another context switch).  This will be slower and use more
CPU than doing it all inside the kernel, without any context switches.

<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at student.uu.se

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