[afnog] CISCO 805 NAT QUESTION

[John Gitau]

> I am currently trying to configure a Cisco 805 to use NAT. 
> Scenario: this router is part of a point-to-point private T1 
> between Nairobi and Ngong Road(my office). The serial 
> interface on this router(Naairobi) connects back to my 
> office(Ngong Road) internal router's serial interface. The 
> connection between the two serial interfaces works fine. This 
> router which is in Nairobi needs to NAT everything going out 
> the fast ethernet interface to 192.168.0.2/ 255.255.255.0.

Depending on the IOS you're running, just run NAT overload. 
'http://www.cisco.com/en/US/products/hw/routers/ps380/products_configura
tion_guide_chapter09186a008007cdf0.html#42572'

I'll give a quick example of how you can quickly go about the
econfiguration. Change the interface names to whatever you need.
! 
! establish the Ethernet interface as an inside interface.
Interface fastethernet 0/0
Ip address 192.168.0.2 255.255.255.0
Ip nat inside 
!
! Next establish the serial interface as an outside interface.
Interface Serial 0/0
Ip address 62.23.5.3 255.255.255.252
Ip nat outside
!
!
access list 1 permit 192.168.0.0 0.0.0.255 ! Modify this to suit you
ip nat inside source list 1 interface serial 0/0 overload
!
!
The above configuration enables packets having the source address in the
range of 192.168.0.0 to 192.168.0.255 to be translated to the globally
unique IP address assigned to the router serial port 0/0 (62.23.5.3) and
vice versa.Multiple local addresses (192.168.0.0 to 192.168.0.255) in
this case use the same globally unique IP address (overloading).

I hope that helps.

					**Gitau
			Safaricom "The better option"
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"If the entire earth, land and water, were covered with computers, 
IPv6 would allow 7x10^23 IP addresses per square meter.  [...]  While it
was not the intention to give every molecule on the surface of the earth
its own IP address, we are not that far off."
	.. Tannenbaum, .Computer.Networks., 3rd Edition
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