Encapsulation Failed on Cisco 2651 2

[JakeTurner2651]

Hi,

I have a Cisco 2651 Router and am trying to connect it to my Virgin Cable Internet service. Below is the current setup:

[Internet] --> [Virgin Super Hub (192.168.100.1)] --> [(192.168.100.2) Cisco 2651 (192.168.40.1)] --> [(192.168.40.2) Laptop]

I am having an absolute nightmare with it. I work at an Entanet and so have shown the config to my colleagues and we just can't understand it. When pinging the Superhub I get responses. However, when trying to ping anywhere past the Superhub I get nothing other than 'Encapsulation Failed'. I have tried putting the cisco onto my internal network (in the same way that the servers and PC's are connected) and again, I can ping the server hosting DHCP and all other servers and PC's in the internal network but nothing past the server hosting the DHCP.

Below is the config as well as the results of the pings. I would extremely appreciate any help as I'd rellay like to get into Cisco routers.

Thanks in advance.

Router-01#sr
Building configuration...

Current configuration : 1122 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router-01
!
!
no ip subnet-zero
!
!
no ip domain lookup
ip name-server 208.67.222.222
ip name-server 208.67.220.220
!
ip dhcp pool defaultepool
network 192.168.40.0 255.255.255.0
default-router 192.168.40.1
dns-server 192.168.40.1
!
!
!
!
!
!
!
!
!
!
!
!
mta receive maximum-recipients 0
!
!
!
!
interface FastEthernet0/0
ip address 192.168.100.2 255.255.255.0
ip nat outside
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.40.1 255.255.255.0
ip nat inside
duplex auto
speed auto
!
ip nat inside source list 1 interface FastEthernet0/0 overload
no ip classless
ip route 0.0.0.0 0.0.0.0 FastEthernet0/0
ip http server
!
!
access-list 1 permit 192.168.40.0 0.0.0.255
!
call rsvp-sync
!
!
mgcp profile default
!
dial-peer cor custom
!
!
!
alias exec s show ip int bri
alias exec sr show run
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
password abc_123
login
line vty 5 15
password abc_123
login
!
!
end

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

When I attempt to ping 192.168.100.1

Router-01#debug ip packet
IP packet debugging is on
Router-01#debug arp
ARP packet debugging is on

Router-01#ping 192.168.100.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.100.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
Router-01#
*Mar 1 00:07:16.498: IP: s=192.168.100.2 (local), d=192.168.100.1 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:16.502: IP: s=192.168.100.1 (FastEthernet0/0), d=192.168.100.2 (FastEthernet0/0), len 100, rcvd 3
*Mar 1 00:07:16.502: IP: s=192.168.100.2 (local), d=192.168.100.1 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:16.502: IP: s=192.168.100.1 (FastEthernet0/0), d=192.168.100.2 (FastEthernet0/0), len 100, rcvd 3
*Mar 1 00:07:16.506: IP: s=192.168.100.2 (local), d=192.168.100.1 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:16.506: IP: s=192.168.100.1 (FastEthernet0/0), d=192.168.100.2 (FastEthernet0/0), len 100, rcvd 3
Router-01#
*Mar 1 00:07:16.506: IP: s=192.168.100.2 (local), d=192.168.100.1 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:16.510: IP: s=192.168.100.1 (FastEthernet0/0), d=192.168.100.2 (FastEthernet0/0), len 100, rcvd 3
*Mar 1 00:07:16.510: IP: s=192.168.100.2 (local), d=192.168.100.1 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:16.510: IP: s=192.168.100.1 (FastEthernet0/0), d=192.168.100.2 (FastEthernet0/0), len 100, rcvd 3
Router-01#

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

When I attempt to ping 8.8.8.8

Router-01#ping 8.8.8.8

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:

*Mar 1 00:07:38.510: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:38.514: IP ARP: creating incomplete entry for IP address: 8.8.8.8 interface FastEthernet0/0
*Mar 1 00:07:38.514: IP ARP: sent req src 192.168.100.2 000a.f493.d2a0,
dst 8.8.8.8 0000.0000.0000 FastEthernet0/0
*Mar 1 00:07:38.514: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, encapsulation failed.
*Mar 1 00:07:40.514: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:40.514: IP ARP throttled out the ARP Request for 8.8.8.8
*Mar 1 00:07:40.514: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, encapsulation failed.
*Mar 1 00:07:42.513: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:42.513: IP ARP: sent req src 192.168.100.2 000a.f493.d2a0,
dst 8.8.8.8 0000.0000.0000 FastEthernet0/0
*Mar 1 00:07:42.513: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, encapsulation failed.
*Mar 1 00:07:44.516: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:44.516: IP ARP: sent req src 192.168.100.2 000a.f493.d2a0,
dst 8.8.8.8 0000.0000.0000 FastEthernet0/0
*Mar 1 00:07:44.516: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, encapsulation failed.
*Mar 1 00:07:46.520: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, sending
*Mar 1 00:07:46.520: IP ARP: sent req src 192.168.100.2 000a.f493.d2a0,
dst 8.8.8.8 0000.0000.0000 FastEthernet0/0
*Mar 1 00:07:46.520: IP: s=192.168.100.2 (local), d=8.8.8.8 (FastEthernet0/0), len 100, encapsulation failed.
Success rate is 0 percent (0/5)
Router-01#

 

[dgrizzard]

Either...

1) The router on the segment 192.168.100.0/24 doesn't know where 8.8.8.8 is (or anything else on the internet) or...

2) There is not a router on that segment to take the request

I would get with Virgin cable to find out what your next hop router is instead of just sending it out the interface. When you do this it just sends a broadcast with an all 0's MAC address (you can see that in your debug) since it does not know the MAC of the next hop router. If the router is not accepting broadcasts then it wouldn't reply, or for whatever the reason is, it is not replying.

Shortly after doing a ping if you do a sho ip arp or sho arp, you should have one or more incomplete entries that will timeout after a couple of minutes and be removed.

 

[ADB100]

ip route 0.0.0.0 0.0.0.0 FastEthernet0/0

Next-hop....

Although you specify FastEthernet0/0 as the default-route this is reliant on proxy-arp being enabled on the device that will forward the traffic on for you. The 2651 tries to find a MAC address to forward the traffic to on the FastEthernet0/0 interface but doesn't have one so it bails.

Delete the IP route statement and add one to point to a real next-hop (192.168.100.?) instead of FastEthernet0/0.

Andy

 

[JakeTurner2651]

Hi guys,

Thank you for your suggestions... You've both hit the nail on the head. I posted this onto the Cisco small business forum and within 20 minutes got a response saying that Proxy ARP was obviously not supported by my ISP and therefore specifiying the interface on the Default route would fail. And, like you both have said, I changed from using the interface to using the IP address of the cable modem (192.168.100.1) and now my router is connected up to the Internet like a charm.

Thank you guys. I really appreciate the help.

Jake Turner