From: Greg Schmitt (GSchmitt@xxxxxxxxxxxxx)
Date: Sun Oct 08 2000 - 15:52:32 GMT-3
Rena,
Think of this in terms of an ISP. The interface connecting you to your ISP
is not normally extracted from your registered IP space. It is usually one
from the providers space. What the provider does is advertise to the world
that he (she) has a route to your address space, and set his (her) router
with a static address for your address space to the outside interface on
your router (e0). With that setup, the returning packets go to your router
via the providers static mapping, and your router takes care of the rest.
Cheers,
Greg Schmitt
22 Jan Halifax :-0
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Geatti
Sent: Friday, October 06, 2000 7:51 PM
To: ccielab@groupstudy.com
Subject: RE: ip nat question
Hey Rena,
You can use the outside address or anything that is routable to that device
such as a loopback that has been propagated into your routing protocol. This
means that the pool address range is advertised and can traffic can find
it's way back.
Take care,
Marco
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
aiqun hu
Sent: Friday, October 06, 2000 1:00 AM
To: ccielab@groupstudy.com
Subject: ip nat question
Hello Group,
Is it necessary to set up the global IP address pool belong to the same
subnet as the outside interface? If not, I don't know how the traffic being
routed back.
For example, the following config is from URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/n
p1_r/1ripadr.htm#xtocid587531
Example
ip nat pool net-208 171.69.233.208 171.69.233.223 prefix-length 28
ip nat inside source list 1 pool net-208
!
interface ethernet 0
ip address 171.69.232.182 255.255.255.240
ip nat outside
!
interface ethernet 1
ip address 192.168.1.94 255.255.255.0
ip nat inside
!
access-list 1 permit 192.168.1.0 0.0.0.255
access-list 1 permit 192.168.2.0 0.0.0.255
--------------------------------------------------
Pool net-208 is the global outside address range for internal subnet
192.168.1.0 and 192.168.2.0. And the nat outside interface address is
171.69.232.182, which belong to another subnet. If E0 connect to Internet,
for example, the default GW should belong to the subnet of Interface E0. Let
say using 171.69.232.183 for default gateway for outgoing traffice. So all
the internal IP address(192.168.2.0 and 192.168.1.0) will be converted to
171.69.233.208/28 subnet address, but using 171.69.232.183 as default
gateway to go out. When the traffic coming back, it won't send to E0 if the
destination address ranges don't belong to the subnet of E0. Feel free to
correct me if I misunderstand something. Any feedback will be appreciated.
Thanks,
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