Routers Cant Ping

[mnoote191]

Michael Noote       

I have been testing out various things in packet tracer before I take ccna I just started with my studies but

I have nat enable on 3 routers they are all using frame-relay from every other devices in the 3 different network they can all ping each other just not my routers I was wonder if anyone can explain why everything else can ping from one network to the next network but I cant ping from one router to the other router

[Richard Burts]

We do not have sufficient information to be able to identify the problem yet. There are several possibilities to consider:

- perhaps there is inconsistency in how the interfaces are configured. Perhaps you could post the output of show ip interface brief from each of the routers and indicate the interface on which the routers are connected.

- perhaps there is inconsistency in the way that frame relay has mapped IP addresses to dlci, Perhaps you could post the output of show frame-relay map from each router.

HTH

Rick

[tobyarnett]

I agree not enough info.

Common troubleshooting steps:

Show IP into be. See interface status
Show IP route x.x.x.x. see the route for your targeted network
Show log. Look for alerted messages


Are your links up? Do you have routes to all nodes? Are you using dynamic or static routing? Are your configs correct?

-Toby


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[mnoote191]

I appreciate all the help it looks like my issue is not with routes I am using rip
V 2 all routes or on all other routers everything else can ping I believe it is NAT that is preventing me from pinging or they way I have it setup I have my sub interfaces on the serial set with NAT outside and local sub interfaces set with NAT inside I am no expert and I am sorry I am unable to produce the configuration of each router right now but all interfaces are all up and again only the routers can't ping each other

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[tobyarnett]

Then give us a diagram or IPS even if moc'd. There are too many possible issues with your configs to make guesses on what the issue maybe.

Toby


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[mnoote191]

Michael Noote I have attached my configurations of all three routers I am new to cisco and I am still learning a lot self taught from books I have a lot to learn but anyway thanks for all the help

[tobyarnett]

Michael,

My first question should obviously be answered but I still need to ask. Are all your links UP/UP. Your DLCI's don't line up so i am guessing you have an intermediate device you havn't listed where these Serial links tie into?

Second your config is pretty basic and it should work i would recommend that you use the overload statement on your R2 device and see if that works. This should provide you with the same process your trying to accomplish.

R2:

no ip nat inside source static 192.168.70.4 200.20.0.2
no ip nat inside source static 192.168.70.4 200.30.0.2

ip nat inside source static 192.168.70.4 Se0/0/0.1 overload

ip nat inside source static 192.168.70.4 Se0/0/0.3 overload

Now with that said, I got to be honest I have never sent the same inside NAT to multiple outside interfaces. I can see the benefit from doing that, and equally I don't see any reason it wouldn't work so long as your routes are there.

If I were setting up this network I would probably use a Loopback0 on each of your routers. I would then use the IP range in the Loopback to NAT to and then I can route that traffic out to any interface I needed. In the event you have an IP address limitation this setup would work, but something to think about.

-Toby

[mnoote191]

Michael Noote let first off thank you Toby for all your help and input I will try the stuff you recommended I have already tried to input the

ip nat inside source static 192.168.70.4 Se0/0/0.1 overload

ip nat inside source static 192.168.70.4 Se0/0/0.3 overload

it wont let me it once another ip instead of the serial interface I dont know enough to know if this is a limitation in packet tracer or the router model I am using the 2621XM which is in packet tracer.

I am just getting started with my studies I passed the CCENT in November on the 15th that was hard enough for me since all I had at the time was Cisco books to read and I used some training videos by Chris Bryant. I am just now 2 months later studying for the rest of the CCNA I decided to go the two exam route so I have one down one more to go I am trying to study on my off time at work. With all this said I know this network I setup in Packet Tracer is basic I am going through all the exam topics on my print out from cisco what will be on the exam and they vlans, nat, wide area networks, stuff like this so as I go through the exam topics I am trying to implement the basics of each of these requirements and teach myself how everything works through videos that I find online and the one cisco book I have at my desk to use for the second half of this exam. I dont have anyone to show me anything so I apologize if somethings I say or show you with my network makes not a lot of since.

Thanks,

Michael

[tobyarnett]

No worries. We have all been there.

Well lets talk basics. Try this on your R2 device:

Remove one of your static NAT's and see if the traffic works. (try to identify if it is the multiple statics or not)

You can also apply the ip nat inside to your F0/0 interface and then see if your trace works (both nat's or one nat)

The "inside nat" command is just identifying the interface where your traffic will originate. You have many subinterfaces and they would technically be all allowed, but you can control what is NAT'd via an ACL statement.

I know your going through your lessons so I am hoping I am not suggesting something outside of that. I just like to simplify things as best as possible when an issue arises. Let me know what works and what doesn't and we can go from there.

I don't have a 2600 in my lab, but if your still having an issue i can try loading these configs on my lab on Monday with some 2800's and see what the problem is.

-Toby

[mnoote191]

Michael Noote Thank you I will go ahead try what you said and thanks for all of your help very much appreciated

[mnoote191]

Michael Noote well I went to site 1 I removed all nat stuff inside and outside the on all the interfaces I removed both inside nat commands on that router and the access-list I am sure I probably didnt have remove all that but I went ahead I can ping from that router to every other router but not from every other router back to that one I assuming its still because the rest have the nat on the interfaces or inside nat command

I guess what I dont understand is why would nat stop the pinging from just the routers and why not everything else from one device on one network to another device on the other network

I know obviously I dont exactly know all of what I am doing but to me it makes no sense

[mnoote191]

Michael Noote Hey Toby

I removed nat off every router and of course everything pings I guess either the inside source commands I had were preventing pinging or me placing

ip outside nat to the subinterface instead of the whole serial interface

and same goes for the fastethernet interfaces I placed nat on the sub interfaces not the interface itself

well I dont think the fastethernet interfaces having nat inside had anything to do with anything because I was trying to ping between the just between the routers on their serial interfaces so maybe I can only see is that really it must be the ip nat outside being added to the sub interfaces that would prevent the ping because the inside source command should only affect what the inside ip address is translated to when trying to access it from the outside

I could be way off but now I can ping

Thanks

[mnoote191]

Michael Noote Hey

I just wanted to say thanks again and after I applied the

ip nat outside commands to just the serial interfaces on each router and not their sub interfaces

everything pings

I also did the same using the ip nat inside commands to local interfaces and that works as well

I seems like everything works now thanks alot

[tobyarnett]

Michael,

That's great. I am glad the issue is fixed. Thanks for the update.

Would you please close the question as answered and rate any helpful comments.

Thanks again,
Toby


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