Showing results for 
Search instead for 
Did you mean: 

Routing problem with packet tracer


Hello everyone,

I'm learning the ropes of networking with packet tracer and I need a little help.
Here the sample network I've been working on.
I have a LAN with some VLANs connected to a router on a stick, cisco 2811. No problems on this end.
That router is connected to one of the 6 routers owned by the ISP.
They are connected to each other in a partial mesh using OSPF protocol.
Supposing now to have 5 more LANs connected to as many ISP routers.

The problem is that I can't ping devices through the ISP network.
I just can ping the first IPS router.
Of couse I missed something...
Please have a look at the attached .pkt sample.
Thanks in advance anyone who wanted to give me some advice and corrections on it.

1 Accepted Solution

Accepted Solutions



from which IP address to which IP address can you not ping ? Did you open the file I sent ?

View solution in original post

10 Replies 10

Georg Pauwen
VIP Master VIP Master
VIP Master



I have looked at your file. The problem is (all) IP addressing. Four of your routers do not have IP addresses at all. The rest of all IP addressing is wrong. In all, my guess is to fix this, it will take a couple of hours at least.


What are the requirements for the IP addressing ? The file says the public ip address space is Where are the 10.x addresses coming from you are using ?



to get you started, I fixed the IP addressing and static routing so you have connectivity between Router0 and the Server. File attached.

Hello Georg,

I didn't mention all the details, sorry. I configured just 3 router in the mesh to start.

I saw I forgot to set the gateway on the server but I still can't ping it. I don't understand what is wrong with ISP4 routers.

Concerning your first question, I suppose I got the meaning/use of public ip address space very wrong so I used 10.x addresses to connect the ISP routers and 51.x for connection to the ISP ones...

Could you please just give me some advice on how to use them in the proper way? 







from which IP address to which IP address can you not ping ? Did you open the file I sent ?


everything works in your file. I still can't ping the server from router0 or router 1.

I made some (too many) corrections on my file but I still miss something.

What kind of modifications have you done?

Better if I start from scratch to set up the ISP network and connected routers.

Here is my plan, and my doubts...

If I have understood correctly, first I have to subnet for all the above connections.

For each router connected directly to the ISP ones: set up PAT; static route toward ISP router.

Set up OSPF on ISP routers.

Is it correct? Forgot something?

Any suggestion would be appreciated.

Maybe I can get back with a new (better?) file for review




can you send the file again, including all the changes you have made ? The one I sent, I could ping the server from Router 0.

Hello Georg,


here I am. It seems to work now, up to this point.

Is it correct the use of public IP adresses?





that looks a whole lot better. In order for all routers to have reachability to the network, you need to add a static route on the ISP-6 router, and redistribute that into OSPF:




router ospf 1
--> redistribute static subnets
network area 1
network area 1
network area 1
ip classless
--> ip route


Revised file is attached.



I can't open your file even with the latest version of packet tracer. I guess it is corrupted.

Anyway, I had already set up the ospf on ISP6. It has lost that modification somehow.

From my understanding, I have to add a static route to each ISP router to point the networks behind router0-1-2.

Thanks for your time.



you need the latest version of Packet Tracer, version 8, to open the file. 


You are right about the static routes pointing towards the networks behind the non-OSPF routers. You also need to redistribute these routes into OSPF, as mentioned in my last post.

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Recognize Your Peers