Cisco 881 loses internet connectivity when cable disconnected and reconnected

[canuck15]

ATTACHED: My current running config with sensitive info taken out.

I have a Cisco 881 Router connected to cable
modem.  The router is running IOS 15.1.

I have it configured exactly the same way as an 877 router running IOS 12.1 which does not exhibit the problem.  Just a standard LAN/WAN config with basic routing/firewall.

When the internet connection is lost for any reason and then re-established the router will no longer pass internet traffic unless I reboot the router.

I used Cisco Configuration Professional to configure the router.  The key setting seems to be the Router Static Route.  We have a static IP and I set static route with the "make this the default route" checked.  Then I set forward (next hop) to the IP my ISP gave me as their gateway.

This is exactly the same way I set the 877 router using the same ISP but in a different office.

Every so often the internet is lost due to power outage or the ISP doing something on their end and every time that happens we have to reboot the router which is quite annoying.

I did not have the "permanent route" check mark checked but I do not have it checked on the router that does not have the problem either so I don't think that's it.  Any other ideas.

When I set the static route to "interface" then added the static IP of the next hop it will continue to work for incoming connections but not outgoing.

[spremkumar]

hi Victor

since you are emphasising this as a working config have you ever checked the status of the cable connectivity on the modem when you had this issue?

also have you tried reseting the cable modem before reseting your router? have you noticed any similarity with the hanging pattern like after every 24hrs or 48hrs etc., etc.?

regds

[SCOTT OLDS]

You are not alone. I have seen this on multiple 881 routers using the out of box IOS image. What happens is when a network cable is removed and plugged in again. The router recognizes when the line protocol goes down but not when it comes up again. Sometime I am able to restore connectivity by toggle shut / no shut on interface f4 manually from the console. Otherwise I have to power cycle the router completely. I have seen this on two 881 routers I have here in my office and just let our helpdesk know about this as well. This is costing us time and money. Workaround: Power cycle the 881 after the cable modem or other network uplink has come back up.

xxxxxxxxxxx#sh ver
Cisco IOS Software, C880 Software (C880DATA-UNIVERSALK9-M), Version 15.0(1)M4, RELEASE SOFTWARE (             fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Fri 29-Oct-10 00:02 by prod_rel_team

ROM: System Bootstrap, Version 12.4(22r)YB5, RELEASE SOFTWARE (fc1)

xxxxxxxxxx uptime is 19 minutes
System returned to ROM by power-on
System image file is "flash:c880data-universalk9-mz.150-1.M4.bin"
Last reload type: Normal Reload

[paolo bevilacqua]

it's known defect, update to 15.0(1)M6 and check again.

[ajaju]

Hi

The next time this happens, try giving the 'clear ip route *' command. I think it should come up then. No need to reload the router. If it does come up that way then there is a bug which you may be hitting and downgrading to 15.0(1)m1 should help resolve it..

Regards

Aniruddha

Cisco TAC