Strange kernel messages?

Kevin O'Connor kevin at ziptek-technologies.co.uk
Tue Aug 10 13:36:28 BST 2004


>-----Original Message-----
>From: Grant [mailto:orbman at thingysrealm.myftp.org]
>Sent: 10 August 2004 13:19
>To: kevin at ziptek-technologies.co.uk
>Cc: freebsd-users at uk.freebsd.org
>Subject: Re: Strange kernel messages?
>
>Kevin O'Connor wrote:
>
>>
>>
>>>-----Original Message-----
>>>From: freebsd-users-admin at uk.freebsd.org [mailto:freebsd-users-
>>>admin at uk.freebsd.org] On Behalf Of Grant
>>>Sent: 10 August 2004 11:44
>>>To: kevin at ziptek-technologies.co.uk
>>>Cc: freebsd-users at uk.freebsd.org
>>>Subject: Re: Strange kernel messages?
>>>
>>>Kevin O'Connor wrote:
>>>
>>>
>>>
>>>>It's just arp telling you that both nics are on the same network.
>>>>This will stop arp messages being logged
>>>>
>>>>Sysctl net.link.ether.inet.log_arp_movements=0
>>>>
>>>>Of course sorting out the problem would be better, it's never a good
>idea
>>>>
>>>>
>>>to
>>>
>>>
>>>>run 2 completely different subnets through the same hub
>>>>Regards
>>>>Kevin
>>>>
>>>>
>>>>
>>>>
>>>>>-----Original Message-----
>>>>>From: freebsd-users-admin at uk.freebsd.org [mailto:freebsd-users-
>>>>>admin at uk.freebsd.org] On Behalf Of Grant
>>>>>Sent: 10 August 2004 11:24
>>>>>To: freebsd-users at uk.freebsd.org
>>>>>Subject: Strange kernel messages?
>>>>>
>>>>>Hi,
>>>>>
>>>>>Got a few freebsd servers and i have noticed quite alot of these
>>>>>messages on the console and in the logs.
>>>>>
>>>>>arp: 10.0.0.100 moved from 00:c0:4f:26:a8:83 to 00:08:c7:3b:67:93 on
>fxp0
>>>>>arp: 10.0.0.100 moved from 00:08:c7:3b:67:93 to 00:c0:4f:26:a8:83 on
>fxp0
>>>>>arp: 10.0.0.100 moved from 00:c0:4f:26:a8:83 to 00:08:c7:3b:67:93 on
>fxp0
>>>>>
>>>>>There is two networks one 10.0.0.0/255.0.0.0 and the second
>>>>>192.168.254.0/255.255.255.0
>>>>>
>>>>>The ip 10.0.0.100 is a proxy/gateway running clarkconnect with dual
>>>>>network cards one on 10.0.0.100 and one 192.168.254.100
>>>>>
>>>>>The messages only seem to show up on the freebsd boxes, there is 3
>boxes
>>>>>that show these messages.
>>>>>
>>>>>The first is 10.0.0.222 which has dual cards with the other interface
>at
>>>>>192.168.254.1
>>>>>The second box only has one card with ip of 10.0.0.60
>>>>>The third box only one card again with ip 10.0.0.70
>>>>>
>>>>>These machines are all linked to a 24port 3Com hub... just in case that
>>>>>is the problem :(
>>>>>
>>>>>The question is what is it ? and should i be worried at the amount i am
>>>>>getting of them ? and can it be stopped ?
>>>>>
>>>>>Thanks
>>>>>Grant.
>>>>>
>>>>>ps - The first box runs 4.10 and the second and third are running 5.2.1
>>>>>There is some linux boxes but they dont show any of the messages.
>>>>>
>>>>>
>>>>>------ FreeBSD UK Users' Group  -  Mailing List ------
>>>>>http://listserver.uk.freebsd.org/mailman/listinfo/freebsd-users
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>Hey,
>>>
>>>Thanks for the quick reply!
>>>
>>>So maybe just get myself another hub and then put all the 10.0.0.0
>>>network on that and leave the 192.168.254.0 on the original hub ?
>>>
>>>I still dont quite get why i get them though as they are on different
>>>networks the subnets are different and so is the ranges... would a
>>>switch help instead of a hub ?
>>>
>>>Thanks
>>>Grant.
>>>
>>>
>>>
>>>
>>
>>Ah you want to know why, this comes up every year or so.
>>Lets assume fxp0 and fxp1 are on the 10.0.0.0/8 network and fxp2 and fxp3
>>are on the 192.168.254.0/24 network. (Just 2 boxes in this example)
>>If fxp1 says hello I'm here fxp0 gets the message and builds an arp entry
>>In the form
>>IP address MAC address
>>so far no problem but you have routing enabled and that is saying if you
>>want to reach the 10.0.0.0/8 network route through fxp2 or fxp3 (internal
>to
>>the boxes) and that gives a different MAC address.You have two routes to
>the
>>different networks one internal and the other external through the hub. So
>>what is happening is you are building one arp entry for the internal route
>>and then scrapping it and building a new entry from the external route.
>This
>>is not a fault it is nothing to worry about in this case.
>>
>>This answer is very simplistic and is only designed to allow you to
>>visualize the problem. To fully understand the problem you will need to do
>>quite a bit of reading.
>>
>>If you wish to use a switch it will need to be layer 3 to allow it to be
>>split between the two networks. Two hubs or layer 2 switches will solve it
>>as well.
>>Hope this helps.
>>Regards
>>Kevin
>>
>>
>>
>>
>Hey,
>
>Well i think i will have to pass on getting a layer 3 switch, i just had
>a look at the price of some of them! damn! heh.
>
>I have made a before and after diagram, the before is what it currently
>looks like with these messages popping up and the after is what i think
>would make them stop.
>
>http://orbsrealm.com/rackmount/pub/images/before.jpeg
>http://orbsrealm.com/rackmount/pub/images/after.jpg
>
>I think thats how i could stop these messages, but i just want someone
>to kind of confirm it before i go moving cables :)
>
>Thanks again
>Grant.

Why two gateways between the networks both server1 and the box labeled
gateway/proxy or will you not be routing on server1 or are you being cleaver
and using gated. Apart from that question it seems fine.
Regards
Kevin





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