Cisco 1841: Can ping ip addresses but cannot connect to the Internet

[davidkagimba]

Hi,

I have recently changed ISP and had to configure my router to accomodate the new ISP. But for some reason I cannot seem to connect to the Internet.

My setup consists of the ISP's modem, my router and then a bunch of switches for the LAN.

With the old ISP, the config was as follows:

Interface FastEthernet 0/0

Description LAN Interface

ip address 192.168.5.1 255.255.255.0

ip nat inside

Interface Serial 0/0/0

Description ISP INTERNET LINK

ip address 10.88.96.212 255.255.255.252

ip nat outside

ip name-server 123.108.252.50

ip name-server 123.108.252.51

ip route 0.0.0.0 0.0.0.0 10.88.96.212

ip nat inside source list 1 interface serial 0/0/0 overload

access-list 1 permit 192.168.0.0 0.0.0.255

access-list 1 permit 192.168.5.0 0.0.0.255

Everything worked fine. With the new ISP, the cable modem they provided has one ethernet port which I connect to one of my FastEthernet ports.

I setup the router for the new ISP like so:

Interface FastEthernet 0/0

Description CRS LAN Interface

ip address 192.168.5.1 255.255.255.0

ip nat inside

Interface FastEthernet 0/1

Description ISP INTERNET LINK

ip address 192.167.18.222 255.255.255.252

ip nat outside

ip name-server 51.202.229.132

ip name-server 51.202.229.130

ip route 0.0.0.0 0.0.0.0 192.167.18.221

ip nat inside source list 1 interface FastEthernet 0/1 overload

access-list 1 permit 192.168.0.0 0.0.0.255

access-list 1 permit 192.168.5.0 0.0.0.255

From my router, I can ping the gateway 192.167.18.221. I can ping all devices in my LAN but I cannot connect to the Internet.

If I connect the ISP modem via ethernet cable directly to my laptop, the Internet works so there seems to be a problem with my config.

Would like some assistance. Thanks in advance

[paul driver]

Hello

Can you try give the wan interface of the router the mac address of your laptop and try again

Possibly you can only register one MAC address with ISP and this way you are spoofing the ISP into thinking your laptop is attached

Res
Paul

Sent from Cisco Technical Support iPad App

[davidkagimba]

How do I give the wan interface the mac address of my laptop ?

[paul driver]

Hello

Int xxx(ISP link)
mac-address xxxx.xxxx.xxxx

To find MAC address of PC
====================
Start /run
Cmd

Get mac /v



Res
Paul



Sent from Cisco Technical Support iPad App

[davidkagimba]

Entering the mac address doesn't help.

The problem still persists

[blau grana]

Hi David,

Please remove mac-address command from WAN interface and please upload your running-config.

Also you mentioned that you can ping 8.8.8.8 from router. Can you upload ouput of traceroute/tracert 8.8.8.8 from some of your LAN device, thanks.

Best Regards

Please rate all helpful posts and close solved questions

[davidkagimba]

tracert

------------

Tracing route to google-public-dns-a.google.com [8.8.8.8]

over a maximum of 30 hops:

  1     5 ms     5 ms     5 ms  192.167.18.221

  2     5 ms     5 ms     5 ms  41.202.226.93

  3     4 ms     5 ms     5 ms  41.202.226.5

  4   194 ms   195 ms   196 ms  gigabitethernet1-0-3.marcr1.Marseille.opentransi

t.net [193.251.251.197]

  5   189 ms   187 ms   199 ms  gigabitethernet13-2-1.marcr2.Marseille.opentrans

it.net [193.251.133.209]

  6   190 ms   189 ms   188 ms  tengige2-15-0-9.pastr1.Paris.opentransit.net [19

3.251.131.217]

  7   192 ms   187 ms   187 ms  google-10.GW.opentransit.net [193.251.250.44]

  8   205 ms   188 ms   189 ms  72.14.239.145

  9   186 ms   189 ms   186 ms  209.85.245.70

10   193 ms   197 ms   192 ms  209.85.245.87

11   193 ms   192 ms   192 ms  72.14.238.43

12     *        *        *     Request timed out.

13   193 ms   192 ms   192 ms  google-public-dns-a.google.com [8.8.8.8]

Trace complete.

sh run

-----------

Current configuration : 1564 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname CATHOLIC_RELIEF

!

boot-start-marker

boot-end-marker

!

enable secret 5 xxxxxxxxxxxxxxxxxxxx

enable password xxxxxxxxxxxxxxxxxxxx

!

no aaa new-model

!

resource policy

!

mmi polling-interval 60

no mmi auto-configure

no mmi pvc

mmi snmp-timeout 180

ip subnet-zero

ip cef

!

!

no ip dhcp use vrf connected

!

!

ip name-server 51.202.229.132

ip name-server 51.202.229.130

!

username xxxxxxx privilege 15 secret 5 xxxxxxxxxxxxxxx

!

!

!

interface FastEthernet0/0

description CRS  LAN Interface

ip address 192.168.5.1 255.255.255.0

ip nat inside

duplex auto

speed auto

!

interface FastEthernet0/1

description ISP Internet Link

ip address 192.167.18.222 255.255.255.252

ip nat outside

duplex auto

speed auto

!

interface Serial0/0/0

description OLD INTERNET LINK

ip address a.b.c.d 255.255.255.252

shutdown

!

interface Serial0/1/0

description redundant

ip address w.x.y.z 255.255.255.252

shutdown

!

interface Serial0/1/1

no ip address

shutdown

clockrate 2000000

!

ip classless

ip route 0.0.0.0 0.0.0.0 192.167.18.221

!

ip http server

ip http authentication local

ip nat inside source list 1 interface FastEthernet0/1 overload

!

access-list 1 permit 192.168.5.0 0.0.0.255

access-list 1 permit 192.168.0.0 0.0.0.255

!

control-plane

!

!

line con 0

password P0ssw0rd

login

line aux 0

line vty 0 4

privilege level 15

password xxxxxxxxxxx

login local

transport input telnet

!

end

[blau grana]

Hi David,

Config looks good. traceroute output is from your router, right? Can you upload traceroute from PC in your LAN, I think that internet connection works but your DNS config is probably not correct.

Do you use DHCP in your LAN? I dont see any DHCP config on router. Did you staticly configure your LAN PC? Can you upload ipconfig with traceroute output which I asked earlier? thanks

Best Regards

Please rate all helpful posts and close solved questions

[davidkagimba]

That tracert I uploaded is from a PC in the LAN

Yes I use DHCP in my LAN. DHCP is setup in windows server.

[blau grana · Accepted solution]

Hi David,

If traceroute output is from LAN PC, I would expect that first hop will be 192.168.5.1, not 192.167.18.221 which is ISP gateway.

Can you please upload these output from LAN PC:

ipconfig /all

route print

ping www.google.com

Also as pdriver suggested to try crosscable, I dont think it will be necessary cause it seems that connectivity is up.

Best Regards

Please rate all helpful posts and close solved questions

[davidkagimba]

Yes you are correct. It was the router tracert..

[paul driver]

Hello

Yes please remove the static mac

And try a crossover cable from router to modem

Res
Paul

Sent from Cisco Technical Support iPad App

[davidkagimba]

Don't have a crossover cable here.

Will let you know when I try that

[satya mothukuri · Accepted solution]

Hi,

Its a DNS issue....try to config 4.4.4.4 as ur DNS in your laptop and even in router. it should work.

Regards,

Satya.M