Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

2800 dropping Comcast connectivity after 1 day

This problem has started after comcast made their upgrades on the East coast about two weeks ago and had several problems.... The router is a 2800 series running advipservices 12.4.25e and after what appears to be about 1 day of communication the router or comcast modem stops sending out internet traffic.. If i do a SHUT no SHUT on the interface of my router connected to the comcast modem, the problem is fixed for about another day. So what do I need to look for? We have replaced the modem twice and we now have an SMC business class modem like we should but having the same problem.

Also some important information is that the comcast modem is still using DHCP right now, so I made the changes on the router to make sure it knew it was DHCP..... No fix.

BTW - if i do a show ip nat trans - there are translations on the router.

  Here is the config of the interface and of my static route

interface GigabitEthernet0/0

description Connected to the Internet

ip dhcp client client-id Loopback0

ip address dhcp

ip access-group 102 in

no ip redirects

no ip unreachables

no ip proxy-arp

ip nat outside

ip inspect SDM_LOW out

ip virtual-reassembly

ip route-cache flow

duplex auto

speed auto

no cdp enable

ip route GigabitEthernet0/0 dhcp

Anyone have suggestions on what to look for?

Hall of Fame Super Bronze

Re: 2800 dropping Comcast connectivity after 1 day

Comcast could be forcing clients to change their IP addresses.

Please note your current IP address with the command 'show ip interface brief' and when the problem occurs again, proceed with the 'shut | no shut' routine then verify the new IP address.

If the IP address changes, Comcast is probably terminating the lease without informing the DHCP clients.

You can have the command 'ip dhcp client lease' under the interface to have your router request a new lease

Per the attached config, everything looks fine.