SNAT before IPSec

noa levy noalevy at gmail.com
Tue Jun 5 00:43:59 CEST 2007


Hi All,

I have a setup where I need to SNAT traffic that will be going out via
an IPSec tunnel. The NAT must take place before the IPSec
encryption+encapsulation, so I need the packet to first go through
SNAT and then match an IPSec policy. After being IPSec-ified, I need
the packets to go through routing again.
My question:
SNAT takes place in POST_ROUTING. Can IPSec be applied after that? I
have read that after IPSec the packet gets injected to LOCAL_OUT
again, but when does the actual IPSec policy decision take place?
Won't it happen *before* SNAT? Can I control it?

Thanks,

Noa



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