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Strange DHCP & ARP behaviour


Oblong_Cheese
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Hi all,

 

My home network presently consists of an ADSL modem, connected via a Smoothwall box to my home PCs. Recently I aquired myself a new toy; a Nintendo DS handheld gaming console. So that I may play games online, I've expanded my previously wired-only network to incorporate a wireless access point.

 

Now, the Nintendo DS console, it its network setup options, has the ability to receive network information via DHCP, or you can manually specify it.

 

Using DHCP unfortunately doesn't work, as my Smoothwall box does not reply to any of the DHCPDISCOVER messages that the Nintendo DS console sends out. I suspect this is part of a larger problem, one that I will divulge further.

 

So, if I set my Nintendo DS console up with a static IP and give it all the other necessary network information, upon attempting to contact the outside world, obviously it is going to need to acquire the MAC address of my internet gateway (the Smoothwall box).

 

Long story short, it can't.

 

The DS console sends out many ARP requests for the MAC address of my SW box, but it is in vain, as the SW box never replies to the request. This is made stranger by the fact that if I attempt to ping the DS console from a PC within my network, the PC is able to resolve the MAC of the DS without any issue, as the ARP request for the DS's MAC is responded to by the DS, with an ARP reply.

 

So, the DS is able to talk to the PC's on my network, but not vice-versa.

 

I was wondering if anyone with in-depth knowledge of ARP would be able to shed some light on this. I have many details of this problem, including Ethereal packet analysis, and I am unable to see where or why or how this issue is occuring.

 

There is a thread here on the Smoothwall Community forums outlining many of the more technical aspects of my problem. I hope somebody can help me out, as I am at a complete loss as to a solution!

 

Thanks in advance.

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There's a *very* good bet that your access point is simply sending faster than the nintendo DS can receive - by it's nature the DS's hardware is limited to transmit and receive at 1 or 2 mbit/sec, and most access points I know are configured to blast data through the air far faster than that in most cases.

I'd be willing to bet the replies *are* being sent (as the log would indicate they are) and the access point is simply sending them at too high a rate for the DS to receive them. You should check your options on the access point to see if you can drop the transmit rate down to 2 mbit, if you can't do that though, you will probably have to give up on it or use a different access point.

 

-Stephen

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(oh, and by the way, it's unlikely that the "PC was answered but the DS was not" - more than likely you are just using a switched ethernet network and the targetted response packet isn't being transmitted to your PC where you're monitoring, to save bandwidth.)

Just thought I should mention such.

-Stephen

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(oh, and by the way, it's unlikely that the "PC was answered but the DS was not" - more than likely you are just using a switched ethernet network and the targetted response packet isn't being transmitted to your PC where you're monitoring, to save bandwidth.)

Just thought I should mention such.

-Stephen

 

I've used Ethereal and LinkFerret to verify that no ARP response messages are sent from my SW box to the Nintendo DS; monitoring the wireless transmissions between my DS and my SW box via a wireless adapter on my PC, so the function of switched ethernet is not an issue.

 

The access point is configured solely as an access point, and it is only an 802.11b access point (ie, limited to a maximum 11Mbit). Even when I take a walk outside into my back yard and force the connection quality to drop by introducing a large displacement between myself and the access point (thereby forcing the two devices to re-negotiate their wireless talkings to a slower speed), I still have the same problem.

 

 

This problem is frustrating because it doesn't make any sense.

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I think it's still possible you may be missing something (ethereal + most wifi cards under windows can NOT capture in promiscuous mode; it's essentially the same as being in a switched network)

 

I'm not convinced you've managed to get the AP to communicate at a lower speed, and there may not be a way to do so.

 

If you have an RA2500-based PCI or PCMCIA wifi card around (see http://ralink.rapla.net/) we can both verify whether or not data is being sent, and what rates it is being sent at.

 

-Stephen

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I think it's still possible you may be missing something (ethereal + most wifi cards under windows can NOT capture in promiscuous mode; it's essentially the same as being in a switched network)

 

I'm not convinced you've managed to get the AP to communicate at a lower speed, and there may not be a way to do so.

 

If you have an RA2500-based PCI or PCMCIA wifi card around (see http://ralink.rapla.net/) we can both verify whether or not data is being sent, and what rates it is being sent at.

 

-Stephen

 

Oh I understand where you're coming from now; excuse my ignorance, I wasn't aware that wireless packet capture under XP was such a nightmare. (I've done some reading up on the topic since reading your above post).

 

I will have to source myself a good old 10Mbps hub from someplace and replace my switch with it temporarily, so that I may properly analyse the data traversing my network... though that still won't conclusively identify the source of the problem, it will at least allow us to rule out the SW box being at fault.

 

In which case, it would be fairly safe to assume that the wireless AP is at fault, which is what you're suggesting.

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Well, can you do a packet capture on the Smoothwall system? that would also clear it up quite quickly - or you could put an xp machine with 2 ethernet cards between the two and create a network bridge and capture from that.

 

Off to sleep now, will talk tomorrow.

 

-Stephen

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Well, can you do a packet capture on the Smoothwall system? that would also clear it up quite quickly - or you could put an xp machine with 2 ethernet cards between the two and create a network bridge and capture from that.

 

Off to sleep now, will talk tomorrow.

 

-Stephen

 

Well it turns out the wireless access point I was trying to use is actually incompatible with the Nintendo WiFi service.

 

I had checked nintendowifi.com for the router, but it wasn't listed at all -- I checked back yesterday, lo and behold, there it is with red writing. :lol:

 

So you were right. <_<

 

Thanks for your help too.

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