Ping between Serial interfaces on two Cisco 2610XM routers stopped working

I have 4 Cisco 2610xm routers and two WS-C2950 switches I am configuring to study my CCNA with.  
Router1 has on FastEthernet0/0, and Router2 has on it's FastEthernet0/0. My computer is
These ports are plugged in to a WS-C2950 switch and I can ping both of them either from my computer which is plugged in to the switch as well, or from either router. Because I am up to the part about natting I would like to plug the two routers together. To this end I plugged a DTE to DCE Crossover cable between the serial interface 0/0 on each router. I successfully setup hdlc encapsulation and a clock rate of 2000000 on router1 which has the DCE end of the crossover cable.
I then gave Router1 serial interface the ip of and Router2 serial interface the ip of
From Router1 I pinged router2 by going "ping" It responded with "Success rate is 100 percent (5/5), round-trip min/avg/max = 1/203/1002 ms"
That was the last time it pinged successfully. That happened a few minutes after I configured the serial ports on the two routers and now they can't ping each other. I have done a traceroute from router1 and the first hop goes to like it doesn't know about the serial interface to send traffic. I can still ping the interface on router1 from router1 fine so that interface is up. It seems like I need to configure a route maybe? I have tested routes a little with not much success.
Any ideas?
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Disconnect the Fa0/0 cable and can you ping R2 from R1 over the serial cable?

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Don JohnstonInstructorCommented:
I have done a traceroute from router1 and the first hop goes to
That would indicate that it doesn't know where the (you're using /24 masks, right?) network is.
Verify the interface is up (for both routers) with a "show ip int brief".  
Make sure you are showing the network in the routing table of both routers and that it's showing up as a C(onnected) entry.
If that all looks right, post the config of the two routers.
shaunwoyAuthor Commented:
Thanks for both posting Miftaul and Don Johnston. I tried Miftaul's approach first. Removing the Ethernet cable to and pinging again to see if it would go through the serial cable. It did! I put the ethernet cable back in to interface and ping still worked. I tried traceroute and this time it showed: "Tracing the route to 4msec 2"  So for whatever reason the route went straight to the serial interface instead of trying the ethernet port. Is that because I removed the Ethernet cable do you think? If it helps any, when I go "sh ip route" it still shows: "Host: Gateway" . is the serial interface on the router I am checking routes on. Like it thinks the route to the serial interface on the same router is through the ethernet interface.  
Don Johnston: I have gone "show ip int brief" and it shows on both routers Serial10/0 as "up"
So it is fixed, but any ideas why it works now?
Thanks for your help so far!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.