[THIN] Re: WHY

  • From: "Chad Schneider (IT)" <Chad.M.Schneider@xxxxxxxxxxxxx>
  • To: <thin@xxxxxxxxxxxxx>
  • Date: Wed, 30 Apr 2008 16:23:10 -0500

What we have done...
 
Removed the client IP Pool.  Then set the firewall to take traffic from
the CAG External interface and re-route it into the firewall.  This did
not work for those with IP Pool address.
 
This works for the external web traffic.
 
Chad Schneider
Systems Engineer
ThedaCare IT
920-735-7615

>>> On 4/30/2008 at 4:09 PM, <andrew.wood@xxxxxxxxxxxxxxxx> wrote:

As Steve says – I’d check your gateways in the first instance – might
be that the user’s gateway is incorrect / badlyconfigured and its
redirecting traffic incorrectly.
 

From:thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On
Behalf Of Chad Schneider (IT)
Sent: 30 April 2008 16:09
To: thin@xxxxxxxxxxxxx 
Subject: [THIN] Re: WHY

 

EXACTLY what we are looking at!

 

Chad Schneider
Systems Engineer
ThedaCare IT
920-735-7615

>>> On 4/30/2008 at 9:58 AM, <andrew.wood@xxxxxxxxxxxxxxxx> wrote:

Ah, now I can ...  say you give your user a corporate laptop for
working from home – you want to allow them to browse the internet, like
they do in the office. What you *don’t* want to do is allow that
browsing to adversely impact on your end device and make that that
device a gateway into your network – so *all* outbound traffic from the
remote device comes through the VPN, onto the internal network and then
out again through the corporate proxy and whatever rules and monitoring
you have in place. 
 
I realise thats not as efficient as (say) allowing the user to browse
directly from their own internet connection – but it from an
audit/security point of view that configuration is easier to manage.
 
From:thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On
Behalf Of Berny Stapleton
Sent: 30 April 2008 15:44
To: thin@xxxxxxxxxxxxx 
Subject: [THIN] Re: WHY

 
So why not put some other IP address space, such as if you are using
10.x for your internal use some 192.168 or vice versa on the connections
for the CAG SSL VPN / IPSEC VPN connections and treat think of them as
another interface, as opposed to being part of the internal network. My
thought would be is that unless the traffic is coming down the TX pair
from the switch that connects to the internal interface of your
firewall, and it's addressed in those subnets, it's not internal
traffic.

RE: any filters/caching/auditing/scanning that you've got set up."

Unless this is a limitation of the CAG why not just setup the scanning
to do exactly this, but from the address space of the VPN / IP SEC
sessions instead of the internal network?

I can't see the logic in bringing the traffic through the external
interface decrypting it, forcing it in across the internal interface (As
that's not where the routing table is going to send it by default) to
get your scanning and then routing it again onto the external
interface.

Berny

2008/4/30 Chad Schneider (IT) <Chad.M.Schneider@xxxxxxxxxxxxx>:

"Otherwise, someone connecting on the external interface is being
routed straight out onto the web – bypassing any
filters/caching/auditing/scanning that you've got set up."

 

This is exactly my point.

 

If they connect and get an internal IP, with an internal default
gateway, all traffic to the outside, should be routed through the
inside.....

 

"unless the destination address is the internal network, why SHOULD it
send it via the internal interface? "  This is also a good point.  I
know this worked fine when we had an Astaro firewall.  The thought is
that the Astaro is Linux, and Linux would note that it was an internal
IP and simply send it out the internal interface.

 

 

Chad Schneider
Systems Engineer
ThedaCare IT
920-735-7615

>>> On 4/30/2008 at 8:33 AM, <andrew.wood@xxxxxxxxxxxxxxxx> wrote:

I'd have thought that if the routing address on your internal interface
was correct,  that all traffic going through the CAG should head through
the internal interface – and then be routed out through the normal
channels for internal network traffic to the internet (which is unlikely
to be the CAG)
 
Otherwise, someone connecting on the external interface is being routed
straight out onto the web – bypassing any
filters/caching/auditing/scanning that you've got set up.
 
This doesn't help Chad mind – other than agreeing with him that whats
happening sounds wrong 
 
a.
 
From:thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On
Behalf Of Berny Stapleton
Sent: 30 April 2008 14:26
To: thin@xxxxxxxxxxxxx 
Subject: [THIN] Re: WHY

 

OK, maybe this is just me and my limited experience with CAG...

A VPN session which I presume is a connection from the internet
(External) to the CAG, the CAG being a gateway device between external
internet and internal network, when you bring up a VPN session, or in
this case I presume IPSEC policy between the two devices (Client PC and
the CAG) which would give you a IPSEC policy to the CAG and any traffic
you send to it through the IPSEC policy would end up on it's local
routing table. At which point it has to make a routing decision about
where to send the traffic, it's an external address so therefore it
would send it to the external interface and therefore external address.

That seems logical to me. My question to you is, unless the destination
address is the internal network, why SHOULD it send it via the internal
interface? My only educated guess on this one is that you used part of
your INTERNAL address space for the addresses you assigned to the CAG
for it to hand out to clients, when as far as I can see, the clients
should have been treated or thought of as DMZ interfaces / connections.

This is just what I am thinking about having done firewall admin
before. 

If I am wrong on this one, and completley off base, please let me know,
my experiece with CAG is limited.

Berny

2008/4/30 Chad Schneider (IT) <Chad.M.Schneider@xxxxxxxxxxxxx>:

Does a VPN session to the CAG, route external bound internet traffic
through the CAG external interface, rather than through the CAG Internal
interface?

 

I am watching the traffic, from our CAG internal IP range, when making
a request to google.com, the traffic goes out the CAG INT0(External).

 

 

Chad Schneider
Systems Engineer
ThedaCare IT
920-735-7615

 

 

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