Penetration Testing mailing list archives

Re: VPN protocols

From: Chris Kuethe <chris.kuethe () gmail com>
Date: Wed, 22 Dec 2004 10:48:57 -0700

On Wed, 22 Dec 2004 09:04:16 -0800, John Forristel (SunGard-Chico)
<John.Forristel () sungardbi-tech com> wrote:

GRE and ESP are protocols, not ports, so they are transported through on
configured ports.  In Cisco, you permit gre and esp through for the VPN
traffic.


No, they are not transported on configured ports. They are transported
via IP, and your IP stack is informed of this by the 10th byte of the
IP header. In tcpdump parlance:

(ip[9] = 47) GRE
(ip[9] = 50) ESP

-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?

Current thread:

VPN protocols Dan Tesch (Dec 22)
- RE: [in] VPN protocols Curt Purdy (Dec 22)
- <Possible follow-ups>
- RE: VPN protocols John Forristel (SunGard-Chico) (Dec 22)
  - Re: VPN protocols Chris Kuethe (Dec 22)
- RE: VPN protocols Keith Pachulski (Dec 22)