DHCP snooping - Misdirected packets

[Stephane Lefebvre]

Hi,

Could anyone help me to understand what are misdirected packets drops in DHCP snooping statistics ?

C3-2960#sh ip dhcp snooping statistics detail 

 Packets Processed by DHCP Snooping                    = 321072

 Packets Dropped Because 

   IDB not known                                       = 0

   Queue full                                          = 0

   Interface is in errdisabled                         = 0

   Rate limit exceeded                                 = 0

   Received on untrusted ports                         = 0

   Nonzero giaddr                                      = 0

   Source mac not equal to chaddr                      = 0

   No binding entry                                    = 0

   Insertion of opt82 fail                             = 0

   Unknown packet                                      = 0

   Interface Down                                      = 0

   Unknown output interface                            = 300

   Misdirected Packets                              = 10878

   Packets with Invalid Size                           = 0

   Packets with Invalid Option                         = 4727

Thanks

Stephane

[lpassmore]

Hi Stephane

A quick look at Google found this link.

https://supportforums.cisco.com/discussion/10885481/dhcp-snooping-statistics

The key answer is

Misdirected

Number of packets that was dropped due to having an address that would have caused the packets to be punted.

http://www.cisco.com/en/US/partner/docs/ios/sbc/command/reference/sbc_01.html

With regards,

[Stephane Lefebvre]

Hi,

Yeah I found that too, but Ithat's not very clear for me : do you have an example to illustrate that ?

Thanks & Regards

Stephane

[lpassmore]

Sorry, no real examples, but if you are unsure what punted means there is a heap of documentation on that.  Basically it is to do with the cef vs process switching of packets. Any packet that is forced into the processor is a punted packet.  If your switch gets its address via DHCP then the count might be for packets that are directed to the switch itself.  Or maybe CEF is not running?