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jimburdon

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problem with Ethernet port on cisco 1721 router

When swapping out my linksys router with a cisco 1721 router I lose internet connectivity. I also can't ping the router's ethernet port. The ports have been configured with the ip addresses obtained from my isp.
I have an Ethernet 10MBPS WIC card, and the built-in FastEthernet card. I know the cables are connected correctly.
Here's a copy of the show config command (ip addresses have been amended for security purposes):
Router#show config                  
Using 691 out of 29688 bytes                            
!
version 12.2            
service timestamps debug datetime msec                                      
service timestamps log datetime msec                                    
no service password-encryption                              
!
hostname Router              
!
boot system flash                
logging queue-limit 100                      
enable secret 5 $1$MG6r$sXRqjwQ6sH0Ixi0tp0sJN/                                              
!
username james privilege 15 password 0 xxxxxxxx                                              
ip subnet-zero              
!
!
!
!
!
!
!
!
!
!
!
!
interface Ethernet0                  
 ip address 69.102.228.226 255.255.255.252                                          
 full-duplex            
!
interface FastEthernet0                      
 ip address 64.167.168.54 255.255.255.248                                      
 speed auto
!
ip classless
ip http server
ip http authentication local
ip http secure-server
!
!
!
!
line con 0
line aux 0
line vty 0 4
 privilege level 15
 password xxxxxxxxx
 login local
 transport input telnet ssh
!
!
end


Any ideas? Hopefully something really obvious that I'm missing.....
Avatar of Joel_Sisko
Joel_Sisko
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So to paraphrase problem:

You had a Linksys connected to you ISP router/modem/bridge, then you replaced the Linksys with the Cisco router, and now you do not have Internet connectivity? But when you place the Linksys back it works, right?

If the above is correct, the IP address you have is more than likely still binded to the mac address of the ethernet port of the Linksys.

Silly question, did you turn off the ISP router also? Turn off everything, unplug any switches connected to the routers. Turn on ISP box, then Cisco router, then your network. Also if this does not work you may need to call your ISP and have them make sure the ARP table is correct in their network device.

Kindet regards
Avatar of CBozeman
CBozeman

Also check the duplex setting for your ISP connection.  I assume int eth0 is your
connection to your ISP, a lot of broadband connections only support half-duplex.  Another item to check is to see if you need a crossover cable between the cisco and the ISP.

BTW, don't forget to add your default route to your cisco config.

CBozeman
Avatar of jimburdon

ASKER

Still not working. I did turn everything off, and then switched on the isp router, followed by the cisco router and then the switch. Initially I could ping the cisco lan interface and the wan interface but still could not get out to the internet. But after a while I could not ping either interface. I then switched everything off again and then on again and the same thing happpened. My pings stopped working after a time.
I do not know what default route to add - is this important?
I did change the int eth0 connection back to half duplex.

I then switched back to my linksys router and low and behold this didn't work! Maybe the ip address of this had been reset?

I'm not back to going out direct through the modem.

So any ideas on what to do to get the cisco router working?
Thank you for your suggestions so far..
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Avatar of CBozeman
CBozeman

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Work with CBozeman on the routing part he should be able to help you since he caught the missing parameter.

In regards to your ISP connection DSL, Satellite, Cable or other?

Depending on your ISP's network, the ARP/DHCP tables do not refresh as quickly as you plug equipment in and out. So, sometimes leaving it unplugged for 15 minutes helps out.

So that could explain why when you went back to the Linksys it did not work (sometimes you need to default the Linksys to clear all the settings and re-configure)

Kindest regards