Simple Question

joeyconcrete · ‎05-27-2003

Hi all,

I'm just starting out with the whole CCNA thing and I've been playing with Routersim. To start I thought I'd do a basic setup - unfortunately it doesn't seem to work as I expected.

The setup is;

[HOST A - 10.2.0.2/16 GW.10.2.0.1]

||||

[int fastEthernet 0/0 10.2.0.1/16]

[2600 ROUTER]

[int fastEthernet 0/1 10.1.0.1/16]

||||

[HOST B - 10.1.0.2/16 GW 10.1.0.1]

I don't have the IOS config offhand. Basically I've configured the interfaces and made sure they are "no shutdown". I can ping both hosts from the router, which tests the ethernet connectivity. I just can't ping host->host when the traffic traverses the interfaces.

I then thought it'll be because there are no static routes. So I added them;

ip route 10.1.0.0 255.255.0.0 10.1.0.1

ip route 10.2.0.0 255.255.0.0 10.2.0.1

I did a "copy run start" and reloaded the router. Still I cant ping host->host.

When I do a show IP route, it displays the two interfaces and their subnets as connected, it also displays the static routes I've added.

Is this a limitation of the routerSim software and is my config correct? Or have I missed something really obvious?

I havent got access to any "real" routers for another week or so.

All help is appreciated.

lgijssel · ‎05-27-2003

Ok joey, The static routes are not required. The two networks are directly connected so they should always be routed.

A few thing might be missing:

In the 2600 you may need to specify the encapsulation as these interfaces can also be set up as trunks.

A wrong subnetmask somewhere might be another problem. Please double-check.

Any access-lists still present in the config?

The best test is to do it step by step.

1 From host-A to its default gateway

2 From host-A to router interface 0/1

3 From host-A to host-B

if it fails on

1 check connectivity and IP settings on the host and router int FA0/0

2 check interface status on the router

3 check host-B

Goodluck,

Leo

joeyconcrete · ‎05-27-2003

Hi Leo,

Thanks for your reply;

The config is as follows

===================

!

version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname Router-2612

!

enable secret xxxxx

!

ip subnet-zero

!

interface FastEthernet0/0

ip address 10.1.0.1 255.255.0.0

no ip directed-broadcast

!

interface FastEthernet0/1

ip address 10.2.0.1 255.255.0.0

no ip directed-broadcast

!

interface Serial0/0

no ip address

no ip directed-broadcast

shutdown

!

interface Serial0/1

no ip address

no ip directed-broadcast

shutdown

!

no ip classless

!

line con 0

line aux 0

line vty 0 4

!

end

===================

From HostA :

I can ping its default gateway, I can ping the other interface (0/1), unable to ping HostB

From HostB :

I can ping its default gateway, I can ping the other interface (0/0), unable to ping HostA

So it seems its not routing the traffic out of the opposite interface. I've checked the IPConfigs on both hosts and their IP/Subnets are set correctly.

HostA - 10.1.0.2/16 gw 10.1.0.1

HostB - 10.2.0.2/16 gw 10.2.0.1

The show ip route displays;

====================

Gateway of last resort is not set

10.0.0.0/24 is subnetted, 2 subnets

C 10.2.0.0 is directly connected. FastEthernet0/1

C 10.1.0.0 is directly connected. FastEthernet0/0

====================

By interface encapsulation do you mean PPP, framerelay or suchlike? Would that matter on a plain jane ethernet network?

There are no access lists in place.

The only oddity is when i do a show interface command, interface 0/1 displays a 0.0.0.0 for its internet address, yet shows as 10.2.0.1 in the config and it responds to a ping! There are no duplicate addresses on hosts or anything.

Starting to look like its a routerSim problem, or have i missed something

Thanks again

Joe

milan.kulik · ‎05-27-2003

Hi,

try

ip classless.

This might help.

Regards,

Milan

lgijssel · ‎05-27-2003

IP clasless will not make a difference as both networks are directly connected. If it does, the simulation is not correct.

Leo

lgijssel · ‎05-27-2003

Joe,

By encapsulation I mean something like:

encapsulation dot1Q / ISL

As far as I can see, your config should work on a router.

I have no experience with the router simulation software so it could be anything. Most likely it is something with RouterSim.

Leo

ranljr · ‎05-27-2003

Joey,

Have you enabled IP Routing?

# conf t

(config)# ip routing

(config)# cntrl-z

# copy run star

#

Hope it helps

rich_sends