relearning 6 addrs per min; mac address 02 01 00 00 00 00

I couldn't find a solution to my problem in this group so I am posting this in hopes that you may find it useful.

Problem:

I started getting these messages in my cisco 3500xl cluster logs every minute.

%RTD-CLUSTER_MEMBER_7-1-ADDR_FLAP: FastEthernet0/9 relearning 6 addrs per min

sh mac showed a mac address of 0201.0000.0000 coming from FastEthernet0/9 along with the real mac of the nic card bound to the ip address. The host was a Windows 2003 server running the network load balancing service. This service was generating the 02:01:00:00:00:00 mac transmission.

Solution: go to network connection properties and look for the service named network load balancing and uninstall it. This will cause the server to disconnect for a moment so beware if you are using a remote console or your users are logged on.

ADDR_FLAP RTD-CLUSTER_MEMBER %RTD NLB Broadcom NetXtreme 5751 Gigabit Controller

Reply to
Danny
Loading thread data ...

--> 1. %RTD-1-ADDR_FLAP [chars] relearning [dec] addrs per min Normally, MAC addresses are learned once on a port.Occasionally, when a switched network reconfigures, due to either manualor STP reconfiguration, addresses learned on one port are relearned on adifferent port. Howeve r, if there is a port anywhere in the switched domainthat is looped back to itself, addresses will jump back and forth betweenthe real port and the port that is in the path to the looped back port. Inthis message, [chars] is the interface, and [dec] is th e number of addressesbeing learnt.

Recommended Action: Determine the real path (port) to the MAC address. Use the debug ethernet-controller addr command to see the alternate path-port on which the address is being learned.Go to the switch attached to that port. Note that the show cdp neighbors command is useful in determining the next switch. Repeat this procedureuntil the port is found that is receiving what it is transmitting, and removethat port from the network.--<

I guess you could use the 'mac-address-table static' command and add the MAC address to the table, that way, it would not have to be relearned...

Regards,

Naz

Reply to
nazgulero

--> 1. %RTD-1-ADDR_FLAP [chars] relearning [dec] addrs per min Normally, MAC addresses are learned once on a port.Occasionally, when a switched network reconfigures, due to either manualor STP reconfiguration, addresses learned on one port are relearned on adifferent port. Howeve r, if there is a port anywhere in the switched domainthat is looped back to itself, addresses will jump back and forth betweenthe real port and the port that is in the path to the looped back port. Inthis message, [chars] is the interface, and [dec] is th e number of addressesbeing learnt.

Recommended Action: Determine the real path (port) to the MAC address. Use the debug ethernet-controller addr command to see the alternate path-port on which the address is being learned.Go to the switch attached to that port. Note that the show cdp neighbors command is useful in determining the next switch. Repeat this procedureuntil the port is found that is receiving what it is transmitting, and removethat port from the network.--<

I guess you could use the 'mac-address-table static' command and add the MAC address to the table, that way, it would not have to be relearned...

Regards,

Naz

Reply to
nazgulero

--> 1. %RTD-1-ADDR_FLAP [chars] relearning [dec] addrs per min Normally, MAC addresses are learned once on a port.Occasionally, when a switched network reconfigures, due to either manualor STP reconfiguration, addresses learned on one port are relearned on adifferent port. Howeve r, if there is a port anywhere in the switched domainthat is looped back to itself, addresses will jump back and forth betweenthe real port and the port that is in the path to the looped back port. Inthis message, [chars] is the interface, and [dec] is th e number of addressesbeing learnt.

Recommended Action: Determine the real path (port) to the MAC address. Use the debug ethernet-controller addr command to see the alternate path-port on which the address is being learned.Go to the switch attached to that port. Note that the show cdp neighbors command is useful in determining the next switch. Repeat this procedureuntil the port is found that is receiving what it is transmitting, and removethat port from the network.--<

I guess you could use the 'mac-address-table static' command and add the MAC address to the table, that way, it would not have to be relearned...

Regards,

Naz

Reply to
nazgulero

But - the address is "locally defined" - so windows load balancer is probably sending it out on multiple ports from the server, or from multiple servers in a cluster.

Turning it off will fix the cisco issue, but probably break the application / server which cant be good.......

The classic fix was to connect all the load balancer LAN connections to a hub and then put that onto the switch - but that woudl limit the aggregate thruput to 100 Mbps 1/2 duplex.

in w2k you could run the load balancing software with different network setups - maybe the same is true here?

what used to be possible was to use a multicast dest address for the load balancing and unique MACs from each server, or a multicast as a source address - but no idea how 2003 has "fixed" this.

maybe your m$oft people can set up the server differently? - as it isnt going to work well like this.

Reply to
stephen

Setting up an etherchannel to the server will fix this too, and work better than the M$ load balancing mechanism.

Reply to
David West

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.