Re: Simple routing question

ralph.collins · ‎02-12-2005

I have a simple test setup :

(The SMC router is also connected to the hub)

Both routers are 2501's running RIP V2. The routing tables look fine. I can ping back and fourth between the two computers but I cannot ping the SMC router. I tried the 0.0.0.0 route entry but it doesn't seem to work. What am I missing? My plan is to have computer1 be able to access the internet through the SMC router.

Here are the configs:

Router 1:

Current configuration:

!

version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname Router2

!

enable secret xxxx

enable password password

!

ip subnet-zero

!

process-max-time 200

!

interface Ethernet0

ip address 192.168.5.1 255.255.255.0

no ip directed-broadcast

!

interface Serial0

ip address 192.168.100.1 255.255.255.0

no ip directed-broadcast

!

interface Serial1

ip address 192.168.4.2 255.255.255.0

no ip directed-broadcast

encapsulation frame-relay

shutdown

frame-relay interface-dlci 105

!

router rip

version 2

network 192.168.5.0

network 192.168.100.0

!

ip classless

!

snmp-server community public RO

!

line con 0

transport input none

line aux 0

line vty 0 4

password test

login

!

end

----------------------------

Router 2:

!

version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname Router2

!

enable secret xxxx

enable password password

!

ip subnet-zero

!

process-max-time 200

!

interface Ethernet0

ip address 192.168.5.1 255.255.255.0

no ip directed-broadcast

!

interface Serial0

ip address 192.168.100.1 255.255.255.0

no ip directed-broadcast

!

interface Serial1

ip address 192.168.4.2 255.255.255.0

no ip directed-broadcast

encapsulation frame-relay

shutdown

frame-relay interface-dlci 105

!

router rip

version 2

network 192.168.5.0

network 192.168.100.0

!

ip classless

!

snmp-server community public RO

!

line con 0

transport input none

line aux 0

line vty 0 4

password test

login

!

end

Thanks

Georg Pauwen · ‎02-12-2005

Hello Ralph,

I think you accidentally posted the config of Router2 twice. Can you post the config of Router1, as well as of the SMC router ? The SMC router is connected to the same hub as Computer2 and Router2 ?

Regards,

GP

Richard Burts · ‎02-12-2005

Ralph

You appear to have pasted the same config twice (at least both configs have the same host hame and have exactly the same IP addresses on the interfaces). Perhaps you need to try again.

If you can ping between the PCs then that is a good indication that routing within your small network is working ok. If you can not ping the SMC there are a couple of things that occur to me that may cause this:

- SMC may be configured to not respond to pings (lots of routers connected to the Internet disable ping).

SMC router may not have a proper route back to your machines.

- SMC router may have an address other than the one that you think that it is.

- SMC router may think the address on your routers is different than what you have configured. Lots of edge routers like to do DHCP for addresses for inside machines. Perhaps SMC is expecting your routers to generate DHCP requests, which they will not do with addresses configured.

You might check on these things and if it still does not work then post the right configs.

Do you have administrative access to the SMC?

HTH

Rick

HTH

Rick

ralph.collins · ‎02-12-2005

Rick, I pasted the correct config this time.

But first..

- I can ping the SMC from another computer on the hub.

- I looked at the configuration on the SMC and don't see any way of giving it a path back to the router.

- As far as the SMC expecting a DHCP request, how would I set the router up for that?

Here's the configs...

Router 1

*********************

Current configuration:

!

version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

service udp-small-servers

service tcp-small-servers

!

hostname Router1

!

enable password test

!

ip subnet-zero

!

process-max-time 200

!

interface Ethernet0

ip address 192.168.2.75 255.255.255.0

no ip directed-broadcast

no ip mroute-cache

!

interface Serial0

ip address 192.168.100.3 255.255.255.0

no ip directed-broadcast

no ip mroute-cache

clockrate 500000

!

interface Serial1

no ip address

no ip directed-broadcast

no ip mroute-cache

shutdown

!

router rip

version 2

network 192.168.2.0

network 192.168.100.0

!

ip classless

!

line con 0

transport input none

line aux 0

transport input all

line vty 0 4

password test

login

!

end

Router 2

*********************

Current configuration:

!

version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname Router2

!

enable secret xxxx

enable password password

!

ip subnet-zero

!

process-max-time 200

!

interface Ethernet0

ip address 192.168.5.1 255.255.255.0

no ip directed-broadcast

!

interface Serial0

ip address 192.168.100.1 255.255.255.0

no ip directed-broadcast

!

interface Serial1

ip address 192.168.4.2 255.255.255.0

no ip directed-broadcast

encapsulation frame-relay

shutdown

frame-relay interface-dlci 105

!

router rip

version 2

network 192.168.5.0

network 192.168.100.0

!

ip classless

!

snmp-server community public RO

!

line con 0

transport input none

line aux 0

line vty 0 4

password test

login

!

end

Thanks for the help

Ralph

ralph.collins · ‎02-12-2005

Rick, I noticed that if I ping from within router2, (thats the one that is connected to the hub with the SMC) I get responses from the SMC router. I can't do that from router1. If that helps.

Ralph

mhussein · ‎02-13-2005

The SMC router doesn't have a route back to router1. To be exact, the SMC router has only 2 routes, a 0.0.0.0 route to the internet and a directly connected route to 192.168.5.0. That is why it possible to ping it only from computer2 and router2 because they are directly connected on the same subnet. The SMC router is not aware of subnet 192.168.2.0

If it is not possible to add a static route on the SMC to subnet 192.168.2.0 (computer1 and router1's eth interface), then you may want to consider NAT'ing that subnet on router2:

interface Ethernet0

ip nat outside

interface Serial0

ip nat inside

ip nat pool blah_blah_pool 192.168.5.2 192.168.5.254 prefix 24

ip nat inside source list 5 blah_blah_pool

access-list 5 permit 192.168.2.0 0.0.0.255

*** you may need to tweak the NAT/access-list to avoid re-using the existing ip addresses on subnet 192.168.5.0

HTH

Mustafa

ralph.collins · ‎02-13-2005

Mustafa, Thanks that makes sense. I'll give that a shot.

Ralph

vnirmal112 · ‎02-13-2005

Hi,

If i am not wrong, NAT May not be of great help in Cisco 2501 Router.It might overload the router if Internet Traffic is more from/to Router 1.

Do u ve a proper Internet Firewall in place. If there is no Firewall, it might result in excess of unwanted packet hits to the network.This will in turn choke ur Internet Bandwidth.

This will reflect on the performance of the Router.

Please revert for further inputs.

Nirmal.

vnirmal112 · ‎02-14-2005

Hi,

NAT Will not be a viable option.Please give a static reverse route and assign access-lists to respective interfaces,thereby preventing unwanted packets to enter the network.

Nirmal.

dataline · ‎02-14-2005

Yeah Agreed with Mr.Nirmal.Ff u are having acsess to SMC router plz put reverse static route for router 1's subnet OR host based routing for both Router 1 & pc1.

ralph.collins · ‎02-14-2005

Ok, all set. The SMC didn't allow for adding static routes or rip. I found a netgear router lying around that did. I set it up for RIP on the LAN side and it all went to work. I appreciate all of the help!