isp dhcp failure on wan interface of 871

[cgoesch]

my 871 router will acquire a dhcp address from cox, and will work for awhile. After a seemingly random amount of time, I lose connectivity out the wan port. A release dhcp and renew dhcp at this point will fix the problem for another 'random' period of time. A linksys router has been working fine at this location for 2 years.

bringing same router into my work, it will not receive an ip address at all from our campus dhcp server. a computer hooked to this same port connects with no problems.

i also tried wiping out startup config, and only entering the following which yielded the same results:

ip address dhcp

no shutdown

i can statically assign an ip address to the wan interface, and everything works just fine.

as far as ios, i was initially using:

c870-advipservicesk9-mz.123-8.YI2.bin

then upgraded to the following which made no difference:

c870-advipservicesk9-mz.124-6.T.bin

i've been searching everywhere for a solution with nothing - and have asked cisco guys at work who tell me my config should work as is both at home and at work.

i'm thinking that i am either missing something simple, or i perhaps have a hardware problem.

[cgoesch]

Hopefully a replacement will fix that problem.

However I am still confused about one other thing - if you are willing to help me troubleshoot that would be great -- otherwise I will move on.

neither one of my 871's will acquire an ip address from my work lan, or my linksys router at home.

But I hook up a cisco 806 running c806-k9osy6-mz.123-22 and it will acquire an ip address everytime, with no problems.

what I did for 871 & 871w

1: erase start

2: int fa4

3: ip address dhcp

(also tried ip address dhcp client-id FastEthernet4)

4: no shut

for the 806:

1: erase start

2: --806 was configured by default with below settings for Ethernet1:

ip address dhcp

[owaisberg]

I was under the impression that you can acquire IP address but loose connectivity

in while after that.

Now, if connecting to the same LAN one router

is capable to acquire address and another one not using the same config then we are talking

of a differences in DHCP client functionality.

I understand that debugging DHCP didn't

produce any results but I find it strange as

I understood that at home you could get an IP

so we should have see DHCP process in debug

outputs.

Please confirm.

Thx,

OW

[cgoesch]

sorry for the late reply I have been out of town for a few days.

At home connected to a Cox Business line, both of my 871 routers would receive an IP address, but one of them would lose connectivity after a random period of time (even though a show ip route still showed the route as good).

At work connected to our campus network, neither one of the 871's will receive an IP address whereas an 806 will work with no problem.

Hooked into a cheapo linksys router yields the same results which I see at work (neither router will acquire an ip address).