I have the following scenario: 1 headquarter , 2 remote sites. Each site is having 2 connections: 1 internet 1 vpn. 3 cisco routers connect together the vpn links and all 3 sites, each of them having 2 interfaces. In headquarter I have ISA 2006 as firewall and internet gateway.
The actual setup in headquarter points all workstations towards the cisco equipment, which decides who goes where, ISA being the default gateway of cisco.
Does anyone have a good reason for changing ISA to be the default gateway for the local lan, routing the packets intended to the remote sites towards the cisco?
Posts: 2228
Joined: 12.Apr.2004
From: Taylorville, IL
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Does anyone have a good reason for changing ISA to be the default gateway for the local lan, routing the packets intended to the remote sites towards the cisco?
No. Because it would be wrong,...bad,... Asynchonous Routing = Evil
You are already doing it correctly. The VPN Device is "doubling" as both a VPN Router and a LAN Router,..which then uses the local ISA as it's Default Gateway. This keep the routing Synchronous Synchronous Routing = Heavenly
Thank you for the answer. Is this sinchronous or asyncronous routing documented somewhere? I mean my setup was somehow logical, putting the most clever equipment first and then the dumber one, but few others from the tech dept. are questioning my decision. I would like to reply them somehow documented :-)
Posts: 2228
Joined: 12.Apr.2004
From: Taylorville, IL
Status: offline
It has nothing to do with smart equipment or dumb equipment. It is the way TCP/IP functions and how sessions state is maintained an monitored. If you receive an ACK packet without out ever receiving the SYN packet that proceeded it then the session state is broken (or spoofed) and should be dropped. The only thing the "dumb" equipment does is not monitor the state and lets the traffic pass when it shouldn't.
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All Forums >> [ISA 2006 General] >> General >> default gateway ISA or CISCO 
default gateway ISA or CISCO - 
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