CJS
join:2008-02-26
Encinitas, CA
| Why does my router have three MAC addresses?
I have the ubiquitous Linksys WRT54G router, and when I go into its configuration settings under "Status", I can choose either "Router", "Local Network", or "Wireless." All of those sections list a MAC address that is slightly different--only the last hex digit varies:
quote:
Router: 00:14:BF:D6:CD:29
Local Network: 00:14:BF:D6:CD:28
Wireless: 00:14:BF:D6:CD:2A
So since my router is hooked up to my DSL modem, my DSL modem sees the "Router" MAC address, but any computer that uses the router on the LAN will see the LAN or wireless MAC address, depending on whether they are connected via ethernet or wireless.
So the question is, why are there three MAC addresses for the same router? I thought the whole point of the MAC address was to uniquely identify the router, and I don't see how there would be any networking conflicts if one MAC address was used in all the above three cases. So why not just use one MAC address?
Thanks for any insight/help.  |
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PetePuma
How many lumps do you want
Premium,MVM
join:2002-06-13
Arlington, VA | You need a MAC address per physical interface, not just one for the whole router. You essentially have 3 different segments (WAN, wired LAN, wireless LAN). |
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jimbopalmer
join:2008-06-02
Greenwood, MS
| reply to CJS
How confused is a laptop with both wired and wireless access going to be if those MAC Addresses are the same? What if this router is "inside" another home network the laptop is connected to (one network wireless and another network wired)
MAC Addresses are almost free, use all you want, they will make more.
--
I tried to remain child-like, all I achieved was childish. |
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Bill_MI
Bill In Michigan
Premium,MVM
join:2001-01-03
Royal Oak, MI
 ·EarthLink
| reply to CJS
Design and convention. Three interfaces, three MACs. By design, no two interfaces in the WORLD should have the same MAC. Of course, that doesn't mean it's not bent here and there (MAC cloning for example).
I had an interesting happening with MACs in OpenWrt. Seems they didn't fix up WAN/LAN as separate MACs after default settings. Since you can bridge LAN/WAN in a PPPoE/tunneling-type system - don't try it when the MACs are the same. |
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CJS
join:2008-02-26
Encinitas, CA
| Thanks for the informative replies, everyone. I guess it makes sense that each network interface would have its own MAC address for special cases where they could conflict when used simultaneously. |
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stevech0
join:2006-09-17
San Diego, CA | the idea in networking is that the manufacturer assigns a unique MAC address to every network interface that he manufacturers. There are manufacturer ID blocks of MAC addresses that are coordinated/registered via an authority. |
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rsenthilkuma
join:2008-07-17
600003
|  reply to CJS
Hi,
In WRT54G router have five ports. one for WAN(Internet) and remaining four ports are LAN.
1. LAN port have one MAC address(all ports are bind this Single MAC).(Local Network: 00:14:BF:D6:CD:28)
2. Then WAN Port have one MAC address, and one more MAC address (Router: 00:14:BF:D6:CD:29)
3.Wireless 54G port MAC address. so ur product have 3 MAC address.Wireless:(00:14:BF:D6:CD:2A)
the first 6 digits are vendor code (00:14:BF - Cisco-Linksys )& next 4 digits are product code (D6:CD - WRT54G).
then the remaining two digits are port numbers. so ur three MAC address first 10 digits are same.
in any clarification reply me |
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