12-25-2009 10:15 AM - edited 03-06-2019 09:04 AM
Hi all,
i have 2650xm router directly connected to cable modem.
I have laptop on fa1/0 port and port fa0/0 connects directly connect to cable modem.
My Laptop has IP 192.168.1.2 and its gateway is fa1/0 interface IP 192.168.1.1
fa0/0 interface on router has IP 96.X.X.X.
From my laptop i am unable to access any internet sites also unable to ping the Fa0/0 interface on the router.
i rebooted cable modem and laptop few times no luck.
any ideas which i can try
thanks
mahesh
12-25-2009 08:50 PM
What is the status of the fa0/0 by issuing a command show fa0/0 and are you able to ping the gateway ip 192.168.1.1 ?
Regards
Ganesh.H
12-27-2009 10:05 AM
12-27-2009 10:06 AM
Hi,
status of fa0/0 is up up and public ip is assigned to it.
12-26-2009 01:15 AM
Hi,
Have you enabled NAT on the router?
A sample configuration is displayed below:
interface fa1/0
ip add 192.168.1.1 255.255.255.0
description TO LAN
ip nat inside
interface fa0/0
ip address 96.1.1.1 255.255.255.252
desc TO INTERNET
ip nat outside
access-list NAT-ACL permit ip any any
ip nat inside source list NAT-ACL interface fa0/0 overload
-------------------
And then ping a public ip, say 8.8.8.8 with an internal ip
Ping 8.8.8.8 source fa1/0
!!!!!
Hope that helps
12-27-2009 10:07 AM
hi,
thanks for reply
i have pasted my router config .
i have enabled nat.
still no luck.
please help
thanks
mahesh
12-27-2009 10:21 AM
mahesh
Do you have a default route configured toward your service provide?
Can you post the entire config?
Reza
12-27-2009 02:40 PM
Ol
12-27-2009 03:05 PM
Hi Reza,
thanks for reply i have entire config attached please see my post from today
thanks
12-27-2009 04:13 PM
Hi Mahesh,
I do not see a default route in your config.
ip router 0.0.0.0 0.0.0.0 (the address of the modem)
May be you did not post every thing
HTH
Reza
12-27-2009 04:15 PM
Hi Reza,
when you use ip address dhcp command under wan interface you do not need to maually config this command/
i pasted you all config
thanks
mahesh
12-27-2009 12:24 PM
Hello Mahesh,
I see that your external interfaces takes an ip address by DHCP. This is made by using BOOTP packets that are UDP/IPv4 packets.
Actually, you send out a broadcast request but the answer is directed to your router's fas0/0 MAC address.
The fact that you cannot ping your default gateway may come from a security measure of provider, it is not a sure sign of problem.
The cable modem can act as a simple bridge and the default gateway can be in the head end serving a lot of users.
You say that you are not able to browse the internet from the laptop, have you tried to bypass the DNS function trying to access directly a public ip address that can be pinged?
in the file we see:
S* 0.0.0.0/0 [254/0] via 96.X.Y.Z
have you got this from DHCP or you have configured it manually?
that is you are using
ip route 0.0.0.0 0.0.0.0 96.X.Y.Z 254
or a form including the DHCP keyword:
ip route 0.0.0.0 0.0.0.0 dhcp 254
see
http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_pi1.html#wp1031306
dhcp | (Optional) Enables a Dynamic Host Configuration Protocol (DHCP) server to assign a static route to a default gateway (option 3). Note Specify the dhcp keyword for each routing protocol. |
Was the service working if the PC is connected directly to the cable modem? Could the provider have stored the MAC address of your PC?
from the laptop shell if you try to use the old nslookup tool what you get?
I see that you receive a DNS server that is in a different major network, this should not be a problem but testing the DNS part can help to understand if you have only a DNS issue, or an IP connectivity issue.
Edit:
I have forgotten that you have been able to telnet to the public ip address of your router this should demonstrate IP connectivity.
Hope to help
Giuseppe
12-27-2009 01:46 PM
Hi giuslar,
thanks for reply
in the file we see:
S* 0.0.0.0/0 [254/0] via 96.X.Y.Z
have you got this from DHCP or you have configured it manually?
Answer i got this from DHCP.
Was the service working if the PC is connected directly to the cable modem
Answer yes it works if pc is directly connected to cable modem.
Also i am unable to ping the IP of interface fa0/0 when i am logged on router but i can ping this IP from C>prompt of laptop.
Let me know if you need more info.
also Note i am able to telnet public IP only from my home Lan not from outside.
thanks
mahesh
12-27-2009 10:21 PM
Hi,
Are you able to ping the direct gateway from your laptop that is local lan and if yes try ping from router with extended ping command using source ip as fa0/0 and try ping laptop and run ethereal software on your laptop and capture the packet what exatly is happening when you ping the interface fa0/0 and share your output.
Regards
Ganesh.H
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