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 From:  "Josh McAllister" <josh at bluehornet dot com>
 To:  "Jake S" <jake at agatestreet dot com>, "Tom Obermayr" <to at bla dot net>, <m0n0wall at lists dot m0n0 dot ch>
 Subject:  RE: [m0n0wall] Cisco VPN Client behind m0n0wall
 Date:  Thu, 18 Nov 2004 10:58:33 -0800
The ideal solution would be if m0n0 supported port triggers or
"application helpers" ... IE, m0n0 sees a connection from inside to
outside (port x) and responds by opening port y and NATing it to the
original inside host. It then tracks the outbound connection and removes
the inbound NAT/fw rule when the outbound connection closes.

Linksys (and others I'm sure) do this.

It can also be done with Linux, and if you have the appropriate
conntrack module you can even allow multiple inside hosts to access such
an application simultaneously. It's quite likely there is something
comparable for FreeBSD, but I don't know enough about FreeBSD to be
sure.

How hard would it be to implement these "application helpers" into M0n0?
Or perhaps the better question... how likely is it that this will be
done?

Josh McAllister

-----Original Message-----
From: Jake S [mailto:jake at agatestreet dot com] 
Sent: Thursday, November 18, 2004 8:49 AM
To: 'Tom Obermayr'; m0n0wall at lists dot m0n0 dot ch
Subject: RE: [m0n0wall] Cisco VPN Client behind m0n0wall

Tom,
Glad it works.  Those commands also work on a Cisco PIX firewall using
access lists but you need to do it on both interfaces.  I believe that
is
because ESP and ISAKAMP are not trackable protocols like say... FTP

As far as a kernel module (like ftp-control and ftp-data) I don't think
one
exists yet for this application or at least I have not found one for
Linux
anyways.

Anyone else know of one?

Thank you,
Jake 


-----Original Message-----
From: Tom Obermayr [mailto:to at bla dot net] 
Sent: Thursday, November 18, 2004 7:43 AM
To: Jake S; 'Jake S'; m0n0wall at lists dot m0n0 dot ch
Subject: RE: [m0n0wall] Cisco VPN Client behind m0n0wall

Jake,

thanks, that actually works (at least as a temporary workaround). What I

had to do is allow ESP in, allow dest port 500/UDP in, and do inbound
NAT 
for port 500/UDP to my internal system.

Of course this only works for a single internal IP address, but at least
it 
allows me to access the VPN concentrator for now.

Again for all on the list: I can't turn on tunneling on the
concentrator, 
that's why I was looking for some kind of intelligent solution
(something 
like the ftp module comes to mind).

tom.

At 04:34 PM 11/18/2004, Jake S wrote:
>You will also need the following too:
>
>concentrator IP/src port 500udp to your IP/dst port 500udp and vise
versa
>(also known as ISAKAMP)
>
>I believe that the VPN client uses ISAKAMP for phase I keying and then
ESP
>for phase II xauth.
>
>Thank you,
>Jake
>
>-----Original Message-----
>From: Jake S [mailto:jake at agatestreet dot com]
>Sent: Thursday, November 18, 2004 7:21 AM
>To: 'Tom Obermayr'; m0n0wall at lists dot m0n0 dot ch
>Subject: RE: [m0n0wall] Cisco VPN Client behind m0n0wall
>
>I see.
>
>Perhaps you could open up the following rule on your mono box:
>
>concentrator IP to your IP and vise versa.  Use the protocol ESP for
this.
>
>
>Thank you,
>Jake
>
>-----Original Message-----
>From: Tom Obermayr [mailto:to at bla dot net]
>Sent: Thursday, November 18, 2004 7:16 AM
>To: Jake S; m0n0wall at lists dot m0n0 dot ch
>Subject: RE: [m0n0wall] Cisco VPN Client behind m0n0wall
>
>I have no control over that Concentrator whatsoever, which is the
reason
>why I'm asking. the others are fine, but the one apparently doesn't
have
>that setting for whatever reason, and I have no chance of changing
that.
>
>tom.
>
>At 04:12 PM 11/18/2004, Jake S wrote:
> >Or you could turn on NAT traversal (NAT-T) on your concentrator which
would
> >encapsulate IPSec traffic on UDP 4500 outbound.
> >
> >
> >
> >Thank you,
> >Jake Seitz
> >
> >
> >-----Original Message-----
> >From: Tom Obermayr [mailto:to at bla dot net]
> >Sent: Thursday, November 18, 2004 7:05 AM
> >To: m0n0wall at lists dot m0n0 dot ch
> >Subject: [m0n0wall] Cisco VPN Client behind m0n0wall
> >
> >hi,
> >
> >I do have a problem with a client system using Cisco VPN client
behind
> >m0n0wall. Apparently there are different settings on the Cisco
Concentrator
> >that change the way the VPN connection is established.
> >
> >I have 3 different VPN entries in the Cisco client, two of which work
just
> >fine behind m0n0wall, whereas the 3rd one only works without the
firewall.
> >Looking at the firewall log, it seems that the VPN Concentrator is
trying
> >to connect to the client on port 500/UDP, which fails, of course.
> >
> >Maybe some kind of VPN client detection could be integrated, which
> >automatically detects internal VPN clients trying to establish VPN
> >sessions, and then allows the separate connection back in to go
through?
> >
> >regards, tom.
> >
> >
> >
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>
>
>
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