DNS problem on cisco router

Unanswered Question
Oct 24th, 2009

Hi All,

i have a small network in which i have a router connected to a switch and all the hosts are connected to the switch in different vlans. router is acting as a L3 device to make communication possible between vlans.

problen is that when i ping ip address of google.com it pings but if I try to ping google.com from router, switch and PC it doesn't ping hence i cant browse the internet from my PC.

all the PCs are getting its ip address and other info from dhcp configured on cisco router.

and i've also configured the router for NAT.

what could be the problem.

plz help....

I have this problem too.
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francisco_1 Sat, 10/24/2009 - 06:39

Couple of thing to check...

Is the router issuing default gateway address to your hosts?

Does the router have a route to the internet?

nitsg.gupta Sat, 10/24/2009 - 06:51

thanks for quick reply

yes, default route is configured thats y i m able to ping WAN ip address.

problem is only with fqdn or browsing.

Reza Sharifi Sat, 10/24/2009 - 06:58


You need to configure the IP address of the name server

for example:

ip name-server

You also need to enable

ip domain-lookup

This command is enabled by default, but lots of operators disabled it.



francisco_1 Sat, 10/24/2009 - 07:05

you mentioned you can ping google ip from hosts but cannot access google web page?

francisco_1 Sat, 10/24/2009 - 07:10

try enabling dns server on router and use (This is a DNS server on the net)


or setup dns manaully on a host and try it..

francisco_1 Sat, 10/24/2009 - 07:15

if you can ping but unable to bring up a web page sounds like dns resolution to me. do you wanna try the dns i gave you!

nitsg.gupta Sat, 10/24/2009 - 07:28

some one blocked UDP port no 53 for some R&D. now users can browse the internet.

thank you very much for your time and help.


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