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Cisco 2911 router - cannot ping, traceroute external addresses

Posted on 2014-01-22
Last Modified: 2014-11-30
Hi there,
For some reason my Cisco 2911 has stopped pinging and tracerouting external addresses and domain names.  I vaguely remember it was working and it stopped working right after the snow storms when we had power surges.  Internal clients are at windows 8 and they can ping and resolve external addresses fine.  The problem is my Meraki cisco devices have stopped continuous provision of internet as they see my cisco router 2911 as their default gateway.
The external connection to my router comes from a switch which basically is converting fiber to Ethernet (may this has gone bad)
I am sure since all my Meraki cisco wireless nodes were working fine.  something had happened where I am unable to even ping or traceroute google.com from the router.  Need help.  Attached is my show run, note that all ip name servers had been given to me by my ISP and no major change has been made as things were working fine.  Need help!
Question by:amanzoor
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LVL 11

Accepted Solution

naderz earned 500 total points
ID: 39802268
Can you provide the result of this command on the 2911:

show ip int br | inc up

1. You said "Internal clients are at windows 8 and they can ping and resolve external addresses fine. " 
Question: how are they connected to the Internet?

2. Where (which interface) are the Meraki's connected to?

3. Which interface connects to the switch providing Internet connectivity? Looks like interface GigabitEthernet0/1.420 is the interface. Is that correct?

4. You had mentioned that there were no "major" changes to the network. Have there been "any" changes and if yes, what are they?

5. Is this router the default gateway in your network? Can your computers ping the interfaces of this router?

6. On the switch connecting you to the ISP/Internet do you see link lights for the connected interfaces? What is the state of the lights and what brand/model is the switch?
LVL 11

Expert Comment

ID: 39802273
One more question: what is interface GigabitEthernet0/1 connected to?

Author Comment

ID: 39803895
cisco_2911#show ip int br | inc up
GigabitEthernet0/0    YES NVRAM  up                    up

GigabitEthernet0/0.422     unassigned      YES unset  up                    up

GigabitEthernet0/0.425    YES NVRAM  up                    up

GigabitEthernet0/1         unassigned      YES NVRAM  up                    up  <<<<<........connected to fiber optic converter switch

GigabitEthernet0/1.420     xx.xx.xxx.xxx   YES NVRAM  up                    up  <<<<....internet

GigabitEthernet0/1.801    YES NVRAM  up                    up   <<<....connection to other branch

NVI0                 YES unset  up                    up

1) Yes all my clients can access the internet, DHCP and DNS are provided by my local servers, DG=routercisco 2911
2) All meraki access nodes are connected to my Brocade switch 6450 which is connected to 'interface gig 0/0 of cisco 2911 router
3) correct interface 0/1.420 is internet
4)Just installed few VMware servers.
5) Yes my clients can ping the router at
6) ON the switch which is the fiber optic converter as well:  port 4 is connected to my router and light is green while port 1 is nothing connected but its still green and on.
7) 0/1 is connected to the swtich from ISP (its brocade switch) on port 4 of switch.

I spoke to my ISP as well till now they have no answer as to how I am able to ping externally from my brocade switch and not from the router.  Then we had the access list 101 taken off and were able to ping externally from the router.  ISP guided its not the solution or answer as access list needs to stay.  Still needs help.

Author Closing Comment

ID: 40472563
ISP glitches.  Works fine.

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