1811 and COmcast DHCP trouble

Unanswered Question
Jun 11th, 2010


I have a router 1811 that was configure to use comcast static ip now is need to switched to DHCP.

I have started with a very simple config to try and establish an ip address on f1 or f0 but I can get the 1811 to pick one.

all I have done is:

int f1

ip add dhcp

no shut

if I go to ip int brief I have no IP address. If I do debug dhcp I get it can't get an IP or the IP is not for this device.

Any help would be greatly appreciated.

I have this problem too.
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Reza Sharifi Fri, 06/11/2010 - 14:39

Hi Marley,

In the global config mode try this command:

"service dhcp"

and test again

If still no connection post the configs for your interfaces.



Marley Brown Sun, 06/13/2010 - 17:41


I will try this on Wednesday. I have limited access to Comcast service with DHCP. If you have any other suggestions please let me know and I will try all of it.

Here is my int config:

interface FastEthernet1

description $ETH-WAN$

ip address dhcp

ip virtual-reassembly

duplex auto

speed auto

I am just trying the basics until I can get an IP address.

Thank you,


zartar911 Fri, 06/11/2010 - 18:06

Hi Marley,

If you have an access-list attached to your interface for incoming traffic, make sure you allow bootpc.

"permit udp any eq bootpc any eq bootpc"



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