simple question

Layer 2 - MAC Address, 48 bit unique identifier for a network host participating in an network. MAC address does not imply the network is Ethernet.

Layer 3 - IP Address, 32 bit identifier for a host participating in a IP network.

Beyond that, I would suggest Google.

-mike

Lukasz wrote:

Reply to
Michael Roberts
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Hi all.

What are differences of IP addresses and MAC addresses??

Thanks a lot in advance

Lukasz

Reply to
Lukasz

Not always 48 bit. Can be more, can be less.

Ever seen what MS RAS server sends for mac addresses in DHCP requests over ethernet?

Also, arcnet has 8 bit mac addresses. (just one of the many reasons it's a dead technology)

T. Sean Weintz

Reply to
T. Sean Weintz

Nope. I'm almost afraid to ask, what does MS RAS Server send?

Reply to
William P.N. Smith

A typical one might look something like:

52:41:53:20:90:e4:9d:b9:24:9d:c0:01:01:00:00:00

notice it's 16 bytes instead of the usual 6.

The first four bytes are always 52:41:53:20. Try converting that to ascii and you will see why they chose those bytes ;-)

This has apparently changes since they released wink. But NT3.5 and 4.0 RAS do use those funny MAC addresses.

Reply to
T. Sean Weintz

[Ascii R@S ]

And that doesn't break anything?

Reply to
William P.N. Smith

Only 48 bit addresses conform to the Ethernet/IEEE 802.3 standard, however, that is not the only MAC in the world. As other posters noted, ARCnet used 8 bit MAC addresses as did Apple's LocalTalk (although they didn't call them "MAC" addresses).

-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 228-0803 FAX

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Reply to
Rich Seifert

802.3 says that 802 defines 16 and 48 bits MAC addresses. (I can't seem to find the 16-bit definition in 802-2001?) 802.3 specifically excludes 16-bit MAC addresses. In that sense only 48-bit macs are conformant.

The usual micros~1 ``let's break stuff'' attitude. I always filter on exactly that with my dhcp setup. Then again, I am not forced to run that kind of stuff, so anything looking like it is clearly rogue.

It did have some nice ideas, though.

Reply to
jpd

Is that off-by-one-error intentional?

Apart from filling up all of the DHCP pool if you let it? Apparently the protocol is robust enough to deal with it. Admittedly, I have not dug into its spec to find out if it's legal or not.

Reply to
jpd

16-bit MAC ws allowed in 802.4 ( broadband cable, as used in MAP)
Reply to
phn

A mac address is assigned to a network card at the point of manufacture. An IP address is assigned, when a computer is connected to a network. The mac address is used for communication over a local network. An IP address is used when the data has to pass through a router.

Reply to
James Knott

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