Forwarding another host

[David DeSimone]

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Rodrique Heron <swygue at rodhouse.org> wrote:
>
>  INTERNET
>     |
>  PIX Firewall
>     |
>  SWITCH*---*HOSTA 192.168.2.14
>    *
>    |
>    *
>   HOSTB 192.168.2.27
> 
> ###  /etc/pf.conf
> ext_if = "em0"
> int_if = "lo0"
> 
> host_ip = " 192.168.2.14"
> jail_ip = "192.168.2.18"
> external_host = "192.168.2.27"
> 
> rdr on $ext_if proto tcp from any to $host_ip port 22 -> $external_host port 22
> rdr on $ext_if proto tcp from any to $host_ip port 26 -> $jail_ip port 22
> 
> pass in quick all
> pass out quick all


NAT is always a two-way street.  PF must not only translate packets sent
to another host, it must also receive and translate the REPLY packets
from that host.

In the scenario you paint above, HOSTB will receive packets from HOSTA,
but when generating a reply, the reply will beypass HOSTA and go
directly back to the PIX firewall.

It works in a jail because the jail is "inside" HOSTA and so all reply
traffic from the jail gets seen by HOSTA before going to the network.

Seems to me it would be easier to get the PIX firewall to send traffic
to HOSTB instead of HOSTA.  If that device is outside your control,
probably the easiest thing for you to do is set up a generic proxy, like
"redir" or similar, to copy traffic over secondary connection to HOSTB.

- -- 
David DeSimone == Network Admin == fox at verio.net
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