NAT Trouble

Unanswered Question
Sep 5th, 2008

Hi everyone I am having an issue configuring NAT on my router.

my inside network is

10.10.10.0 /24

my outside network is

192.168.1.1

I want a NAT pool that translates 10.10.10.? into 192.168.1.1 for access to the internet, the serial interface on my router is the 10.10.10.0 network and the Ethernet int is the 192.168.1.1 network. please help with this.

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
Jon Marshall Fri, 09/05/2008 - 12:08

Shane

The following config will achieve what you want. One thing though, are you sure the inside LAN is on your serial interface and the outside interface is the ethernet interface ?

If you have got that the wrong way round just modify the following config. Should be failry obvious what needs changing.

ip nat inside source list 101 interface e0 overload

access-list 101 permit 10.10.10.0 0.0.0.255 any

int s0/0

ip nat inside

int e0

ip nat outside

Jon

shane.kearney Fri, 09/05/2008 - 12:24

ok first jon your a legend, I could only aspire to be as good as you some day, thanks.

I have created my own network at home,

the router that faces the internet is 192.168.1.254 /24 and it has a DHCP pool for the whole subnet, I have an cat 5 from a port on the router to my 1900 switch and another cat 5 from a port on my switch to the e0 on my 2500 router, its ip is 192.168.1.1, now on the serial link from the 2500 the network is 10.10.10.0 this is connected to another 2500 router, the ethernet 0 int on this 2500 is 173.135.168.0 /24, i have configured nat on this router to translate the 173 network into the serial interface but when the ping to 192.168.1.254 gets to the int ser 0 of router 1 it can go no further, it just times out, so need to be able to ping from 173.? to 192.168.1.254, can i do this?

Jon Marshall Fri, 09/05/2008 - 13:02

Shane

"ok first jon your a legend, I could only aspire to be as good as you some day, thanks"

Hmmm, i think you should aspire to something a little bit better than that... :)

Does your setup look like this

Internet - router1 (192.168.1.254) - (192.168.1.1) 2500_1 (s0 - 10.10.10.?) - (s0 - 10.10.10.?) 2500_2(e0 -173.135.168.?)

If you are Natting all the 173.135.168.x addresses to 10.10.10.x 2500_2 then does router1 have a route for the 10.10.10.x network pointing back to 2500_1.

If not and you can't add a route to router1 then you could move the Nat to 2500_1 instead of on 2500_2 and then the 173.135.168.x addresses would be natted to 192.168.1.1. Router1 would know how to get to this address.

Jon

shane.kearney Sun, 09/07/2008 - 22:37

OK after a weekend of trying until the early hours I found the issue, the router I have as the internet facing router is ISP supplied and when I try to ping 173.135.168.X the ISP router bounces the packet into the internet instead of routing in into the internal network. I cannot configure a static route on this “Router” so I have bought a Cisco 837 ASDL VPN router from E-Bay so fingers crossed this works for me. Thanks for your help

Actions

This Discussion