1841 internet access help needed

[ztaylorITSEC]

I have a home lab for CCNP studies and I'm trying to allow one of my routers (1841) to access the internet. As of right now I can ping all the way to my public ip address (Cable Modem) but cannot ping anything beyond that. My setup for the purposes of this discussion is: 1841 F0/0 > Linksys E1200 > Cable Modem. I have the 1841 configured to get it's IP via DHCP from the Linksys. All other clients connected to the Linksys can successfully ping outside so this leads me to believe that the config issue is with the 1841. Any ideas???

Thanks,

Zach

[ztaylorITSEC]

I've attached a topology diagram for clarity. I am assuming that I do not need to configure nat on the 1841 as the Linksys router should already be handling that.

[dkuchenski]

If the Linksys is already NATing for your PC's, then you are right it should be NATing for your 1841.

You have a default route (0.0.0.0 0.0.0.0 Linksys GW) on the 1841, correct?

[ztaylorITSEC]

Sure do! Here's my config:

Here's my config:

R1#sh run

Building configuration...

Current configuration : 973 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

service password-encryption

!

hostname R1

!

boot-start-marker

boot-end-marker

!

!

no aaa new-model

ip cef

!

!

ip auth-proxy max-nodata-conns 3

ip admission max-nodata-conns 3

!

!

no ip domain lookup

!

!

!

interface FastEthernet0/0

ip address dhcp

duplex auto

speed auto

!

interface FastEthernet0/1

ip address 10.10.10.1 255.255.255.0

duplex auto

speed auto

!

interface Serial0/0/0

no ip address

shutdown

clock rate 2000000

!

interface Serial0/0/1

no ip address

shutdown

clock rate 2000000

!

ip default-gateway 192.168.1.1

ip forward-protocol nd

ip route 0.0.0.0 0.0.0.0 FastEthernet0/0

!

no ip http server

no ip http secure-server

!

!

!

control-plane

!

!

line con 0

exec-timeout 0 0

privilege level 15

logging synchronous

line aux 0

line vty 0 4

exec-timeout 0 0

password 7 060506324F41

logging synchronous

login

!

scheduler allocate 20000 1000

end

[dkuchenski]

Try pinging from the 1841 with a source interface of fa0/0 and see if that works (ping 4.2.2.2 source fa0/0).

[Harold Ritter · Accepted solution]

Hi Zach,

You should not need the static route as you get the information from DHCP. If you want to use a static route, you should configure the ip next hop. Using only the egress interface as you do would require arp proxy on the LinkSys and I do not think it is supported.

change the static route as follow:

ip route 0.0.0.0 0.0.0.0 192.168.1.1

or remove the static route altogether and use the one received via DHCP.

Hope this helps

[ztaylorITSEC]

That did it! I just removed the default route altogether and viola! I knew it had to be something simple. Thanks! I tuned ip domain-lookup back on and can even ping dot com's.