What Type Of Address Is 01-00-5e-0a-00-02

Ever seen a MAC address that starts with 01-00-5e and thought, what on earth is that? If you're poking around your network logs or a packet capture and 01-00-5e-0a-00-02 shows up, you're not looking at a normal device MAC. You've stumbled into multicast territory Simple, but easy to overlook..

And honestly, a lot of people freeze when they see it. And it looks like a hardware address, but it isn't tied to one specific laptop or switch. Still, the short version is: it's an IPv4 multicast MAC address, mapped from a multicast IP. So what type of address is 01-00-5e-0a-00-02? But there's more going on under the hood than most quick answers tell you.

What Is 01-00-5e-0a-00-02

Let's skip the textbook talk. A regular MAC address is supposed to be the unique physical ID burned into a network card. But 01-00-5e-0a-00-02 isn't that. It's a reserved address range used for IPv4 multicast on Ethernet Nothing fancy..

The first three bytes — 01-00-5e — are the giveaway. That's the Organizationally Unique Identifier (OUI) assigned to multicast traffic. Practically speaking, anything starting with those six hex digits is not a single machine. It's a broadcast-like delivery address that a group of devices can listen to at once.

Where the Rest of the Bytes Come From

Look at the last three bytes: 0a-00-02. On the flip side, those aren't random. They're derived from the IPv4 multicast group address Worth keeping that in mind..

Here's how it works in practice. Because of that, 0to239. Consider this: 0. So to build the MAC, you take the low 23 bits of the multicast IP and shove them into the last 23 bits of the MAC. Consider this: 0. 255.Worth adding: an IPv4 multicast address lives in the 224. 255.255 range. The 01-00-5e prefix gives you the first 25 bits, with the 25th bit always set to 0.

So 0a is hex for 10, and 00-02 are just 0 and 2. Because of that, 2as the multicast group. 10.Day to day, 0. So naturally, ) Turns out01-00-5e-0a-00-02is the layer-2 face of the224. Flip that into the IP math and you get 224.Here's the thing — 0. 0.0.Day to day, (224. Which means 0 plus 10 in the second octet, 0 in the third, 2 in the fourth. 10.2 multicast group.

And yeah — that's actually more nuanced than it sounds.

Why It's Not a "Real" Device Address

A switch sees 01-00-5e-0a-00-02 and knows not to treat it like a unicast destination. It won't do normal MAC learning on it. Consider this: instead, it forwards frames with that destination to every port that has joined the matching multicast group — or floods them, if IGMP snooping isn't running. That's a big difference from your laptop's 3c-52-82-xx-xx-xx style address Which is the point..

Why It Matters

Why does this matter? That's why because if you don't recognize multicast MACs, you'll misread your own network. I've seen folks swear a mystery device was spoofing MACs, when really it was just a Chromecast or a router sending SSDP traffic to 01-00-5e space.

Multicast is how one sender reaches many receivers without blasting a full broadcast. Video streams, routing protocols like OSPF, mDNS, and Windows discovery all lean on it. 10.In practice, when you see 01-00-5e-0a-00-02, something is deliberately talking to group 224. That's why 0. 2 Nothing fancy..

And here's what most people miss: that group is in the 224.x is actually general-purpose multicast, not link-local. Because of that, 0/8admin scope, but224. So it could be crossing routers if your network allows it. 0.On top of that, 10. 0.Which means x. Miss that and you'll wonder why traffic is showing up where it shouldn't Not complicated — just consistent..

Real talk — ignoring these addresses leads to bad firewall rules, broken VLANs, and switches that flood like it's 1999. Knowing the type saves you from chasing ghosts Small thing, real impact..

How It Works

The mechanics are simpler than they look, but the details are where it earns its keep.

The Mapping Math, Step by Step

1. Start with a multicast IP, say 224.10.0.2.
2. Convert the last three octets to binary: 10 = 00001010, 0 = 00000000, 2 = 00000010.
3. Take those 24 bits, drop the top bit (because the MAC prefix already fixes it), and you have 23 bits: 0001010 00000000 00000010.
4. Prefix with 01-00-5e (which is 00000001 00000000 01011110 in binary, with bit 25 = 0).
5. Result: 01-00-5e-0a-00-02.

That's it. No central registry per group. Consider this: the translation is algorithmic. Which is also why 32 multicast IPs map to the same MAC — but that's a mistake section topic.

How Frames Move on the Wire

A host that wants to receive 224.Here's the thing — 10. The NIC enables a multicast filter for that address. 0.Also, 2 tells its network stack to listen on 01-00-5e-0a-00-02. The sender just addresses the Ethernet frame to 01-00-5e-0a-00-02 and sends one copy.

Switches behave based on IGMP. With IGMP snooping, they track who joined what and forward only to members. Without it, they treat 01-00-5e like unknown multicast and flood all ports. So in a dumb switch, 01-00-5e-0a-00-02 shows up everywhere. In a smart one, only where it's wanted.

The Role of IGMP

IGMP is the glue. Consider this: hosts send "join" messages for 224. 10.Worth adding: 0. On top of that, 2, routers query, hosts report. The MAC is just the delivery label. Even so, iGMP decides who gets the package. Skip IGMP understanding and the MAC looks like the whole story — it isn't And that's really what it comes down to..

Common Mistakes

This is the part most guides get wrong. They stop at "it's multicast, move on." But the real pitfalls are specific.

One: thinking 01-00-5e-0a-00-02 identifies a vendor. It doesn't. The OUI is reserved by the IANA for IPv4 multicast. No company makes a card with that baked in Most people skip this — try not to..

Two: assuming one MAC equals one IP. 0.10.0.That's why 2, 226. 224.0.Here's the thing — 2... 10.Now, 10. That's why because only 23 bits are mapped, 32 different multicast IPs share the same MAC. all become 01-00-5e-0a-00-02. 2, 225.If you're debugging, check the IP layer. The MAC alone lies a little Most people skip this — try not to..

Three: confusing it with 33-33 addresses. Which means those are IPv6 multicast. Different prefix, different rules. 01-00-5e is strictly IPv4. Mix them up and your filter rules break.

Four: blocking all 01-00-5e at the edge without thought. You'll kill DHCP relay, OSPF, and service discovery. I know it sounds simple — but it's easy to miss what depends on it The details matter here. And it works..

Practical Tips

What actually works when you see 01-00-5e-0a-00-02 in the wild?

• Decode the IP first. Run the last three bytes through the 23-bit mapping. You'll know the group in seconds. For 0a-00-02, that's 224.10.0.2.
• Check IGMP snooping on your switches. If it's off, turn it on. Your broadcast domain will thank you. Flooding multicast is how small networks die at scale.
• Filter at layer 3, not layer 2. If you

must restrict multicast traffic, use ACLs on the IP address rather than dropping frames by MAC. A layer-2 block on 01-00-5e is a blunt instrument that takes down unrelated groups and control protocols at the same time.

• Watch for duplicate MACs in captures. If two streams look like they share 01-00-5e-0a-00-02, don’t assume a spoofing attack. Confirm the destination IPs — they are likely just different groups in the same /24 collapsed into one layer-2 address.
• Document your groups. Keep a table of which multicast IPs your applications use and what they map to. When a packet shows up at 01-00-5e-0a-00-02, you should already know whether it belongs there.

Conclusion

The address 01-00-5e-0a-00-02 is not mysterious once you see the mechanism: it is the deterministic Ethernet face of IPv4 multicast group 224.That's why 10. 0.Treat the layer-2 address as a delivery label, not an identity, and base your filtering, debugging, and network design on the group address rather than the hardware address. The MAC tells you where the frame goes on the wire; the IP tells you what it means. 2, produced by a fixed bit-mapping rule and delivered through IGMP-coordinated forwarding. Do that, and multicast stops being a black box and becomes just another routable service And that's really what it comes down to..