10-11-2019 05:19 AM
Hi everyone.
I'm using a Cisco 1921 with a VWIC2-2mft-t1/e1 to convert a T1 handoff from the ISP to a single ethernet.
I configured the T1 and is up, from the router I have internet access(i can ping 8.8.8.8). on the Gigabitethernet 0/0 I have a computer and configured a DHCP server on that port with 10.10.10.0/25. also, I have the default static route pointing to the serial interface.
The problem I'm having is that from the computer I cannot connect to the internet. I'm able to ping only 10.10.10.1 but cannot ping the next hop 4.25.115.102. I attach both my config and static routes. I've tried different static routes but I cannot make it work.
Thank you for any help in advance and let me know if you have any other questions.
Solved! Go to Solution.
10-11-2019 10:50 AM - edited 10-11-2019 10:59 AM
You don't have NAT.
Paste these commands:
ip access list standard NAT
permit 10.10.10.0 0.0.0.127
ip nat inside source list NAT interface Serial0/0/0:0 overload
interface GigabitEthernet0/0
ip nat inside
interface Serial0/0/0:0
ip nat outside
It should work.
10-11-2019 08:00 AM
So can you ping 8.8.8.8 from the router itself, not the PC behind LAN?
10-11-2019 08:01 AM - edited 10-11-2019 08:03 AM
I noticed your have default gateway, not ip route 0.0.0.0. Def Gateway is used for switches.
Can you remove your ip default-gateway 4.25.115.102 and insert ip route 0.0.0.0 0.0.0.0 4.25.115.102 instead?
10-11-2019 08:51 AM
10-11-2019 08:49 AM
Correct I can ping 8.8.8.8 from the router but not from the computer.
10-11-2019 10:50 AM - edited 10-11-2019 10:59 AM
You don't have NAT.
Paste these commands:
ip access list standard NAT
permit 10.10.10.0 0.0.0.127
ip nat inside source list NAT interface Serial0/0/0:0 overload
interface GigabitEthernet0/0
ip nat inside
interface Serial0/0/0:0
ip nat outside
It should work.
10-11-2019 12:44 PM
It is true that the original config did include ip default-gateway. And it is true that this command is not used if ip routing is enabled. But that does not necessarily indicate that the command should be removed. Because the original config also included an ip route 0.0.0.0 0.0.0.0n serial 0. So the routing in the original config was ok. And that is why the router was successful in ping 8.8.8.8. @Filip Knezevic is quite correct that the significant issue is that the original config did not include address translation.
HTH
Rick
10-11-2019 09:35 PM
Hi Richard,
Thanks for the observations. Indeed I missed there was an ip route command as I was in a hurry.
But definitely his issue is that there is no Port Address Translation configured.
I still think it's not bad that the the unnecessary ip-default gateway command was removed, though it wouldn't break anything if he left it.
10-14-2019 09:56 AM
10-15-2019 11:02 PM
Hi Jose,
Glad it's working.
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