IP-6-PHYBCASTDROP

[Ibrahim Jamil]

Hi

i have the below msg appear on my 6500 , what is the reasons and how to sove it

%IP-6-PHYBCASTDROP: Physical broadcast packet detected and dropped,

thanks

[Raju Sekharan]

Hi Ibrahim

1. As per RFC  standard 1812 section 5.3.4,

A router SHOULD silently discard a packet that is received via a LinkLayer broadcast but does not specify an IP multicast or IP broadcast   destination address.

http://tools.ietf.org/html/rfc1812#section-5.3.4

You have received such a packet and router has dropped

2. 169.254.X.X IP range is not a routable IP range. it is reserved range for link-local addressing in Internet Protocol Version 4.

Some of your host has got this IP becasue it didn't receive DHCP IP address and it got this range of I Pas part of microsoft auto-ip

3. If you are receving these messages frequently, then you need to locate the host sending this broadcast

Thank you

Raju

[Ibrahim Jamil]

Hi Raj

Thanks for ur reply

How to locate the host sends this brodcast?

thanks

ibrahim

[Raju Sekharan]

Hi Ibrahim,

You can try capturing the packets with mac-address ffff.ffff.ffff and find out he source mac of those packets to locate the host

Is the error message showing any IP address?

Thanks

Raju

[Ibrahim Jamil]

Hi raj

how do i do that?the mac is 169.254.x.x?pls help me out

thanks

ibrahim

[Raju Sekharan]

Hi Ibrahim,

is your error message showing the MAC address from the packet is coming?

If it is not showing, we have the following options

Oneway is to use Miniprotocl Analyzer to  capture the packet if your IOS supports it. You can filter using an ACL which matches source IP address 169.254.X.X

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SY/configuration/guide/mini_protocol_analyzer.html

There is an easy way if you have only few subnets. Just configure s secondary IP address of 169.254.X.X/16 on your interface. Then give a ping to 169.254.255.255. If you get a reply from any of the host look in the ARP table

show ip arp | inc 169.254

This will show the mac-address of the host. Which you can track

You need to do this on interfaces one by one till you find the host sending this packets

Thanks

Raju

[Ibrahim Jamil]

Hi raj

thanks for ur reply

below is the error msg

src=169.254.61.133, dst=169.254.255.255

thanks

ibrahim

[Raju Sekharan]

Hi

What is the version of code you are running?

Thanks

Raju

[Raju Sekharan]

Hi

Also provide the following output

1. Show module

Thanks

Raju

[Ibrahim Jamil]

Hi Raj

thanks for ur reply

pls find below info

(s72033_rp-IPSERVICESK9_WAN-M), Version 12.2(33)SXI2a

1   48  48-port 10/100/1000 RJ45 EtherModule   WS-X6148A-GE-TX    

  2   48  48-port 10/100/1000 RJ45 EtherModule   WS-X6148A-GE-TX   

  3   48  48-port 10/100/1000 RJ45 EtherModule   WS-X6148A-GE-TX   

  4   48  48-port 10/100/1000 RJ45 EtherModule   WS-X6148A-GE-TX   

  5    5  Supervisor Engine 720 10GE (Active)    VS-S720-10G        

  7  48  CEF720 48 port 1000mb SFP              WS-X6748-SFP

thanks 

[Raju Sekharan]

Hi Ibrahim,

You can do an ELAM to capture this packet

do the following setps

1. test platform service internal enable

2. sh pl ca elam asic sup slot 5

3. sh pl ca elam tri dbus ipv4 if IP_SA=169.254.61.133

4. sh pl ca elam start

Once you get the error message check if ELAM captured the packet

5. Sh pl ca elam status

it will show as completed once it captures the packet

6. Sh pl ca elam da

This will show the packet with source-mac

After this you can track the mac-address and find out where it is connected

Disable the ELAM after you are done

7. test platform service internal disable

Thanks

Raju

[Ibrahim Jamil]

Hi Raju

thanks for ur reply