Simple Routing Issue

[newtocisco2012]

Afternoon Everyone,

Appologies for such a basic question but i'm just getting started with cisco kit so you will have to bare with me.

I have a cisco 1841,

Fa0/0 has the ip of 192.168.5.20

Fa0/1 has the ip of 10.0.0.1

Fa0/0 goes off to the Default gateway of 192.168.5.254

Fa0/1 goes off to a switch where I have a test machine connected (Ip 10.0.0.5).

From the router I can ping 8.8.8.8 for example and it's fine.

From the test computer I am unable to.

I added the "ip route 0.0.0.0 0.0.0.0 192.168.5.254" which then allow the router to ping 8.8.8.8

I realise I am probably making a very basic mistake but would appriciate some points or hints as to where I am going wrong.

Below is the config:

Password:
R1#show run
Building configuration...
Current configuration : 847 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$wssO$VhBou3PyVzg.IbEz4.4xv/
!
no aaa new-model
!
resource policy
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip subnet-zero
ip cef
!
!
no ip dhcp use vrf connected
!
!
no ip domain lookup
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.5.20 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 ip address 10.0.0.1 255.255.255.0
 duplex auto
 speed auto
!
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.5.254
!
no ip http server
!
!
control-plane
!
!
line con 0
line aux 0
line vty 0 4
 password test
 logging synchronous
 login
line vty 5 15
 password test
 logging synchronous
 login
!
end

If anyone could help that would be greatly appriciated.

Am I right in thinking I would have to create some sort of NAT rule from the inside to outside. or am I going down the wrong path here

[cadet alain · Accepted solution]

Hi,

yes you're right, just do NAT and it shall work:

access-list 1 permit 10.0.0.0 0.0.0.255

ip nat inside source list 1 interface f0/0

int f0/0

ip nat outside

int f0/1

ip nat inside

Regards.

Alain.

[newtocisco2012]

Thank you for your fast reply alain.

Just to get this correct so I understand, all we have done here is effectively called fa0/0 outside and 0/1 inside.

A new access list has been created for the network 10.0.0.0

We have then told the router that if any traffic from the inside interface in list 1 matches 10.0.0.0 to send it to the outside interface 0/0

[cadet alain]

Hi,

any source address matching access-list 1 entering the inside interface will get translated to the IP address of the outside interface along with a port number so this is called NAT overload( many to one). So from the outside the source IP is the outside IP.

Regards.

Alain