In article <dnqd13$v3v$1@sunce.iskon.hr>, Robert <robert_abc@net.hr> wrote:
Walter Roberson wrote:
Nothing about this gets interesting until you want to start building
VPN endpoint firewalls with multiple interfaces, with the interfaces
distinguished by VLAN instead of by IP address and with the
possibility
of having the same IP range in different VLANs, to be treated
differently.
Thanks a lot for this! But, could you explain it in more detail for me? I am
not sure what you mean about that VPN endpoint firewalls and that example
you gave.
I was using "VPN endpoint firewalls" to indicate a device that combines
VPN termination and firewall facilities. The Cisco PIX series are
examples of this combination.
The Cisco VPN3000 series is for VPN termination only, and does not have
detailed controls over what can be accessed.
The Cisco FWSM (Firewall Services Module) for the Cisco 6500 & 7600
only does firewalls with no VPN facilities; and the Cisco VPNSM (VPN
Services Module) for the Cisco 6500 & 7600 only does VPN with no
firewall facilities, so if you want a high performance VPN and firewall
on your Cisco 6500 or 7600, you would need to buy a FWSM and a VPNSM
.... at about $US35000 for each of the modules!
.... I have partly written a more detailed explanation of what is needed
and what I was referring to, but it is getting late and I need to head
to bed before I can make the explanation interesting and readable.
Ah, I know: let me turn this around. As this is a learning experience
for you in which you will be required to demonstrate to your
instructor what you learned, then instead of me explaining the
steps, how about if -you- outline the steps involved as far as you
understand them, and we'll comment on your outline.
Suppose you have host A in private subnet X in VLAN 10 at site C
(Client), and you need to get the packet to host B in private subnet Y
in VLAN 10 at site S (Server), and that the two are connected by the
Internet (which only deals with public IP addresses). How would you
safely get the packet from one place to the other?
Assume that, as I described earlier, Layer 2 encapsulation can be
seperated from encryption / VPN, and assume that there are firewalls at
each end. Indicate each step at which a packet changes form or
changes IP address, and describe the logical function that each
of those steps is performing.
Or start with something a bit simpler, such as describing the packet
sequence that would be used for layer 3 traffic in which VLANs were not
involved. There are not really very many steps involved with that.
--
"law -- it's a commodity"
-- Andrew Ryan (The Globe and Mail, 2005/11/26)