05-29-2012 09:07 PM - edited 03-07-2019 06:58 AM
I have upgraded a C3750G-12S-E to c3750-ipserviceslmk9-tar.122-55.SE5
This switch is a distribution layer switch for one of my remote sites. it contains an ip helper-address on the site vlan's SVI.
DHCP relay is no longer functioning for client PCs. Static address assignment allows full network functionality.
I enabled debug ip dhcp server packet
DHCPD: Looking up binding using address [Correct Network Address]
DHCPD: setting giaddr to [Correct Network Address]
DHCPD: BOOTREQUEST from [Client MAC] forwarded to [Correct DHCP Server IP]
DHCPD: option 43 is malformed (option length 0).
DHCPD: invalid DHCP options - unable to parse
I found this: https://supportforums.cisco.com/message/3151175#3151175 containing:
Actually I am betting you upgraded your IOS from something before 12.2(50)SE to 12.2(50)SE or later. We added enhancement CSCso19800 which will validate DHCP options when we are a relay agent.
As your option 61 had Leng 0, its invalid and should not be there.
I am using option 43 for LWAPP Discovery and it functions correctly for other sites. The option contains the IP of my WLC(s).
I currenly do not have any LAPs at this site but will be adding them soon so getting rid of Option 43 is not an option. ( LOL )
Any thoughts?
Your help is much appreciated.
- JK -
05-30-2012 07:12 PM
Any suggestions other than downgrading to an earlier version?
I cannot see how this behavior could be "by design"
06-05-2019 07:26 AM
Hi,
I know this is an old post. did you find a solution for this? I had the same problem this week and temporarily removed the Option 43 from DHCP Scope but that is not a solution as I need it for the AP's to join the right WLC.
06-05-2019 11:57 AM
Issue solved after reading the http://www.faqs.org/rfcs/rfc1533.html and removing an incorrect Option 43 configuration from DHCP.
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