Re: SNAT before IPSec

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Noa,

What can I tell you? You are on your own way ....

My last suggest is use OpenVPN and IPSec.

Best regards,

Jorge Davila.

On Thu, 7 Jun 2007 18:40:35 +0300
 "noa levy" <noalevy@xxxxxxxxx> wrote:
Well, I agree with you in principle, but it's been this way for years,
so routing practices are in place to handle it. I'm trying to recreate
the setup we have now, which is using commercial VPN gateways, with
Linux-based ones, but the addressing scheme is a given, I have no
control over it

On 6/6/07, Jorge Davila <davila@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
Ah!!!!

Noa, in my humble opinion, you *must* assign new addresses to the internal
networks. You may will live a routing nightmare if you decides stay with the
actual address assignment.

Best regards,

Jorge Davila.

On Wed, 6 Jun 2007 02:05:53 +0300
 "noa levy" <noalevy@xxxxxxxxx> wrote:
> The situation here is that several geographically diverse parts of the
> network (several branches of the same company) use the same internal
> addressing space. This was done to make it easy to centrally configure
> the branches. As a result, however, when talking to the center via
> VPN, we have to map each branch's network to another network allocated
> by the center.
>
> Noa
>
> On 6/6/07, Jorge Davila <davila@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
>> Uhm ... well, may another approach works.
>>
>> But, why reports another source IP address to the remote internal
>>network???
>>
>> Jorge Davila.
>>
>> On Wed, 6 Jun 2007 01:40:34 +0300
>>  "noa levy" <noalevy@xxxxxxxxx> wrote:
>> > Yes, I want to change the source IP address of the original IP packet
>> > before encryption.
>> >
>> > On 6/6/07, Jorge Davila <davila@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
>> >> OK - Let me now if I'm wrong ...
>> >>
>> >> Are you trying to modify the source address of the packet before the
>> >>packet
>> >> gets encryption?
>> >>
>> >> Jorge.
>> >>
>> >> On Wed, 6 Jun 2007 00:29:51 +0300
>> >>  "noa levy" <noalevy@xxxxxxxxx> wrote:
>> >> > Thanks for all the help so far.
>> >> > Jorge - I'm actually using the native 2.6 kernel ipsec (netkey) and >> >> > not KLIPS, so I don't have the "ipsecN" virtual interfaces and can't
>> >> > use that.
>> >> > In response to Grant's reply - I think I have a problem, since I'm
>> >> > using the 2.6.10 kernel (can't upgrade anytime soon). Can anyone
>>point
>> >> > me to where I can find the relevant ipsec patches that enable the
>> >> > double passage through netfilter hooks?
>> >> > Thanks,
>> >> > Noa
>> >> >
>> >> > On 6/5/07, Jorge Davila <davila@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
>> >> >> I'm guessing that you can use the "normal" approach and apply the
>>SNAT
>> >> >>rules
>> >> >> to the outgoing traffic flowing in the ipsec interfaces.
>> >> >>
>> >> >> The ipsec encryption algorithm is a kernel space tool and iptables
>>is a
>> >> >>user
>> >> >> space tool to the netfilter kernel module.
>> >> >>
>> >> >> All traffic that pass the POSTROUTING chain in the NAT table is
>>leaving
>> >> >>the
>> >> >> firewall box (through a physical interface e.g.:eth0 or through a
>> >>virtual
>> >> >> interface e.g.:ipsec0).
>> >> >>
>> >> >> Jorge Davila..
>> >> >>
>> >> >> On Tue, 5 Jun 2007 15:29:47 +0300
>> >> >>  "noa levy" <noalevy@xxxxxxxxx> wrote:
>> >> >> > 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
>> >> >> >
>> >> >> >
>> >> >>
>> >> >> Jorge Isaac Davila Lopez
>> >> >> Nicaragua Open Source
>> >> >> +505 430 5462
>> >> >> davila@xxxxxxxxxxxxxxxxxxxxxxx
>> >> >>
>> >> >
>> >>
>> >> Jorge Isaac Davila Lopez
>> >> Nicaragua Open Source
>> >> +505 430 5462
>> >> davila@xxxxxxxxxxxxxxxxxxxxxxx
>> >>
>> >
>>
>> Jorge Isaac Davila Lopez
>> Nicaragua Open Source
>> +505 430 5462
>> davila@xxxxxxxxxxxxxxxxxxxxxxx
>>
>

Jorge Isaac Davila Lopez
Nicaragua Open Source
+505 430 5462
davila@xxxxxxxxxxxxxxxxxxxxxxx



Jorge Isaac Davila Lopez
Nicaragua Open Source
+505 430 5462
davila@xxxxxxxxxxxxxxxxxxxxxxx


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