topic Re: NAT Lab in Routing and SD-WAN

NAT Lab

jsblach — Mon, 26 Jun 2023 06:18:02 GMT

Hi i do have a very simple setup in

GNS3

with two VPCs and two IOUL2 switches.

One switch has the following configuration:

interface Ethernet0/0
switchport access vlan 123
switchport mode access

interface Ethernet1/0
no switchport
ip address 192.168.178.254 255.255.255.0
ip nat outside

interface Vlan123
ip address 192.168.0.254 255.255.255.0
ip nat inside

ip nat inside source list 1 interface Ethernet1/0 overload

access-list 1 permit 192.168.0.0 0.0.0.255

ip route 0.0.0.0 0.0.0.0 192.168.178.1

If i use ping 192.168.178.1 source vl 123 on the switch, everything works fine and i see an entry
in

sh ip nat trans

. But if i ping 192.168.178.1 from an attached vpc it doesn't work.

Where am i thinking wrong?

Thanks in advance!!!

Re: NAT Lab

MHM Cisco World — Mon, 26 Jun 2023 06:07:11 GMT

Did you add

İp routing

To SW?

Re: NAT Lab

Flavio Miranda — Thu, 22 Jun 2023 10:57:56 GMT

It woud be a behavior expected IF the PC has not gateway or wrong gateway

Re: NAT Lab

jsblach — Mon, 26 Jun 2023 06:09:58 GMT

hi, thanks for your answers.

@MHM Cisco World yes, and if i configure

static routing

instead of

nat

i get a reply.

@Flavio Miranda

the vpc have gateways

configured, as i said, routing works

nat

doesn't

Re: NAT Lab

jsblach — Thu, 22 Jun 2023 11:33:12 GMT

here i have the gns3 project attached

Re: NAT Lab

MHM Cisco World — Mon, 26 Jun 2023 06:15:17 GMT

Then dont waste your time' the IOS SWl3 image canot do

NATing.

Re: NAT Lab

jsblach — Thu, 22 Jun 2023 11:24:23 GMT

ok so you would say, that the configuration in general would be correct?

Re: NAT Lab

MHM Cisco World — Mon, 26 Jun 2023 06:14:50 GMT

So so correct'

Your config is perfect but there is some bug in

gns3.

Re: NAT Lab

jsblach — Thu, 22 Jun 2023 11:28:11 GMT

but it does work in this case. why wouldn't it work with a vpc using the svi address as gateway?

Re: NAT Lab

MHM Cisco World — Mon, 26 Jun 2023 06:13:15 GMT

You are learning and you need to sure that you config is correct'

I will apply same config you share in my lab and share reuslt.

I also have

gns3

and after weeks try solve this issue I give up and use

NSK sw

instead.

I will share lab tonight dont worry.

MHM

Re: NAT Lab

paul driver — Mon, 26 Jun 2023 06:14:26 GMT

Hello
instead of using a

VPC node

, use a

rtr

and disable

ip routing

on that router so to make it a host device ( ip address & D/G) and test again.