Cisco 1801 Refuses to Connect to ADSL

Unanswered Question
Jan 9th, 2009

Hi all,

I have a Cisco 1801 Router that is really annoying me. Its brand new out the box. I have a Netgear ADSL modem that I set up in 5 minutes, and this Cisco Router is still annoying me after 8+ Hours of zero success.

I succesfully configured it but it halts on the Test Connection as "Could not ping the DNS Servers". The Green ADSL CD Light is solid on the front of the router when the line is connected.

Unlike the Netgear, the Cisco doesn't show what has failed. Is it the IP Configuration of the Interface? Is it the Username & Password? Who knows as SDM doesn't give you anything to go on.

Everything has been setup using the wizards and the settings all confirmed the same as the operating Netgear modem / ISP Website Settings.

Whats the common reason for failure to get a Ping reply during test if there is one?



I have this problem too.
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Giuseppe Larosa Sat, 01/10/2009 - 13:06

Hello Chris,

have you got a chance to connect to console or to telnet to the router ?

verify the state of interfaces with

sh ip int brief

you should see up up also for the ATM0 or ATM0/0 that is the ADSL line

then try to ping some address in internet

and try to traceroute .

If everyting is fine and you have configured NAT for internal users connect a PC to the client lan fastethernet port and try the same tests.

Then try to browse

May be the problem is only on the DNS or even not a real issue

Hope to help


mszeftawy Sat, 01/10/2009 - 14:34

Hi Chris

using the SDM you will find an option that views the router running configuration

can you send the running config of your router and the information provided by your ISP to configure the router

ChrisWhite85 Tue, 01/13/2009 - 08:32

Hi there,

Thanks for the replies both.

I think I may have found the error (I haven't configured NAT). So the Router is only doing internal routing and not touching the Internet.

I have attached my SDM Router File for your viewing pleasure anyway.


Giuseppe Larosa Tue, 01/13/2009 - 10:27

Hello Chris,

you'r right NAT config is missing you have just placed ip nat inside under vlan1

you need ip nat outside under Dialer4

to define an ACL that describes vlan1 ip subnet

access-list 11 permit

a NAT command with overload option

ip nat inside source list 11 int dialer4 overload

Hope to help



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