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Cisco 891 not getting IP address with DHCP with latest IOS

farid.joubbi
Level 1
Level 1

‎04-27-2015 10:44 AM - edited ‎03-05-2019 01:20 AM

Hi,

I have a few Cisco 891 routers that are configured as DHCP clients on the WAN interface.

For some reason when I boot the router with a late IOS, the router is not receiving an address.

It works just as expected with the older IOSes.

Any ideas of what changed?

 

This is how the interface is configured:

interface FastEthernet8
 ip address dhcp
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 duplex auto
 speed auto
 no cdp enable
 !

This IOS does not work:

c890-universalk9-mz.154-3.M2.bin

While these do work:

c890-universalk9-mz.150-1.M7.bin

c890-universalk9-mz.151-2.T2.bin

c890-universalk9-mz.152-1.T1.bin

 

Doing a "show ip interface brief" shows that FastEthernet8 is unassigned with the affected IOS.

With the older IOSes there is an IP address.

 

I had to downgrade two routers due to this issue, and did not have  plenty of time to troubleshoot.

Both of the routers are connected to DSL from the same ISP...

Anyone seen anything like this  before?

 

2 people had this problem
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2 Replies 2

emurtelcisco
Level 1
Level 1

‎08-08-2015 08:46 AM

Hi, I have the same problem too with a cisco 891F-k9, but there is no IOS version 153. neither 152.

 

how did you solve the issue? thanks

0 Helpful

farid.joubbi
Level 1
Level 1
In response to emurtelcisco

‎08-10-2015 05:34 AM

Hi,

I haven't solved the issue.

I did a wireshark capture of the DHCP request sent from a 891 with both the old and new IOS.

You can see the result here: http://s11.postimg.org/lgkwwok7n/dhcp_req.png

As you can see Cisco added option 60 in the later IOSes, which was not there before. It is not possible to remove it, at least not that I know of.

 

So the question is why the DHCP server is not answering the DHCP request sent from the later IOSes. It could also be that the answer is sent, but the 891 does not accept it.

Unfortunately I am not able to debug or capture real live traffic with the affected routers due to our uptime requirements.

 

Which ISP is it that you have the problem with? Could it be Telefonica?

I would appreciate if you had the opportunity to investigate further and maybe contact your ISP.

Please report any progress.

Thanks.

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