Internet dropping with 861 router and DPC3010 cable modem

[stevenbarnes]

Hi all,

I am having an issue with my network that has me perplexed.

I have a DPC3010 cable modem (Charter internet).

I previously had it connected to a Linksys WRT54GL with DD-WRT installed and that was working ok except that I had to reboot it 2-3 times per week.

I replaced it with a Cisco 861 (non-wireless) router and it worked ok for a few hours then it started dropping the internet connection (it goes up and down constantly)

If I switch back to the Linksys everything works fine again

I am using the same cables in either case so I know it's not a cabling issue

I upgraded the firmware to c860-universalk9-mz.151-4.M3.bin, but it made no difference

I was starting to suspect a problem with the physical ports on the router, but I decided to try connecting the 861 behind the Linksys and turns out it works fine in that setup.

So to recap...

If I connect the 861 directly to the modem my internet connection bounces up and down

If I connect the Linksys directly to the modem my internet connection is fine

If I connect the Linksys directly to the modem and the 861 to the Linksys everything works fine (my PC is connected to the fe0 port of the 861)

Are the 861 and the modem simply incompatible or is it a configuration issue?

I have attached my 861 config to this thread.

Any help you can provide would be greatly appreciated

Thanks in advance

Steven

[Alessio Andreoli]

Hi Steven,

take a look at this:

http://www.cisco.com/en/US/docs/ios/ipaddr/command/reference/iad_dns1.html#wp1013357

it is possible that the option none in the WAN interface is not the one you want:

interface FastEthernet4

description $ETH-WAN$

ip dhcp client update dns server none

ip ddns update hostname myusername.dyndns.org

ip ddns update ccp_ddns1

ip address dhcp client-id FastEthernet4

ip nat outside

ip virtual-reassembly

duplex auto

However, i would suggest to buffer more info in order to understand what is happening. You can type:

conf t

logging buff 16384 deb

end

wr

!

Of course a sho logg would show the info and debugging events could be another way to catch what is happening.

HTH

Alessio

[stevenbarnes]

Thanks Alessio... I am away right now, but I will give your suggestion a try when I return and let you know what happens (it will probably be this evening)

[stevenbarnes]

Sorry it took me so long to get back with you.

It ended up being a problem with my default route

I had... ip route 0.0.0.0 0.0.0.0 FastEthernet4 permanent

and I needed to have... ip route 0.0.0.0 0.0.0.0

thanks