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fulldisclosure logo Full Disclosure mailing list archives

Re: Cisco support multiple pptp (GRE) Channels ?
From: "Joseph Karpenko \(jkarpenk\)" <jkarpenk () cisco com>
Date: Wed, 15 Aug 2007 11:12:27 -0700


-----Original Message-----
From: full-disclosure-bounces () lists grok org uk 
[mailto:full-disclosure-bounces () lists grok org uk] On Behalf 
Of Michael Gale
Sent: Wednesday, August 15, 2007 12:42 PM
To: full-disclosure () lists grok org uk
Subject: [Full-disclosure] Cisco support multiple pptp (GRE) 
Channels ?

Hey,

      Does anyone know if a Cisco firewall can support 
multiple PPTP (GRE) 
channels from internal clients to a single external server ?

yes, you'd need to have 1-1 NAT translations for the clients behind the
firewall.


--snip--
Right now the PPTP server is on the public network and it is working 
correctly for connections from all clients. We have a private network 
from behind a firewall, let's call it firewall A. A single 
client from 
behind firewall A can connect with out a problem, however if a second 
client tries to connect from behind firewall A it looks like 
firewall A 
does not forward the PPP LCP packets.

Am I correct that mutliple GRE (proto 47) tunnels would be a problem 
when the clients have the same IP address?

you got it, there is nothing to identify and differentiate the flows -
hence the reason the PPTP clients need 1-1 NATs.

--
karpenko

--snip--


-- 
Michael Gale

Red Hat Certified Engineer
Network Administrator
Pason Systems Corp.

"What we need are more people who specialize in the impossible." - 
Theodore Roethke

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/


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