I have 2 Cisco 2501s configured back to back via their serial ports. I can ping: -Ethernet port of router1 -Serial ports of both routers I CANNOT ping: -Ethernet port of router2 The same is also true from router2 to router1. All ports are up and running. Any idea what is the problem. Here is my data: ------------------- Router1#sh run Building configuration... Current configuration: ! version 11.3 service timestamps debug uptime service timestamps log uptime no service password-encryption ! ! interface Ethernet0 ip address 192.168.2.1 255.255.255.0 no cdp enable no mop enabled ! interface Serial0 ip address 192.168.3.1 255.255.255.0 no ip mroute-cache no fair-queue ! interface Serial1 ip address 192.168.3.3 255.255.255.0 no cdp enable ! router rip network 192.168.0.0 ! ip classless ! snmp-server community public RO ! line con 0 exec-timeout 0 0 line aux 0 line vty 0 4 password 300 login ! end Router2#sh run Building configuration... Current configuration: ! version 11.3 service timestamps debug uptime service timestamps log uptime no service password-encryption ! ! ! ! interface Ethernet0 ip address 192.168.7.1 255.255.255.0 no cdp enable no mop enabled ! interface Serial0 ip address 192.168.3.2 255.255.255.0 no ip mroute-cache no fair-queue clockrate 56000 ! interface Serial1 ip address 192.168.6.1 255.255.255.0 clockrate 56000 no cdp enable ! router rip network 192.168.0.0 ! ip classless ! snmp-server community public RO ! line con 0 exec-timeout 0 0 line aux 0 line vty 0 4 password 300 login ! end Router2# -

I CANNOT ping: -Ethernet port of router2 The same is also true from router2 to router1 What message is returned? I presume you are pinging each router from the other router.