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RE: Very Strange Incident
From: "Shawn Jackson" <sjackson () horizonusa com>
Date: Tue, 23 Mar 2004 08:23:16 -0800

VPN packet dropped (100R->Vraptor: Protocol=IPSEC-ESP spi=0x4ac80658): 
The packet is either too old or has been received before 
(potential replay attack?) (tunnel 6.isakmp.104 () 100r <VPN-100r>) 

When working on larger WAN's with IPSEC connected sites I've received
that
message if one of the remote VPN terminators clock is off by too much
time.
Usually I setup my NS servers (NS1, NS2, NS3) with NTPd and have them
sync
with some teir1 and tier2 NTP providers, then have all my equipment
point
To them.

As the Cisco was the last hop before the subnet I can't think why
traceroutes 
would be redirected to this new device. Especially as only the ISP has
access 
to the router to make config changes

I don't think it's likely that there is a device trying to 'hack' your
VPN
tunnel. At the very least, it could just be too much lag between the
remote
side VPN and the VPN core. It could also be a malfunctioning router
which is
holding packets in it's transfer cache for too long.

But get info on that device, and slap your IT guy. Can never be too
careful.

Shawn Jackson
Systems Administrator
Horizon USA
1190 Trademark Dr #107
Reno NV 89521

www.horizonusa.com
Email: sjackson () horizonusa com
Phone: (775) 858-2338
       (800) 325-1199 x338

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  • Very Strange Incident Alan Greig (Mar 22)
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