Questions tagged [mac-address]

For questions about Media Access Control (MAC) address which is used as the OSI layer-2 address for many OSI layer-2 protocols.

Filter by
Sorted by
Tagged with
2 votes
1 answer
66 views

cisco catalyst 6500 not honoring static ip assignments

I have a catalyst 6500 sup720 running 15.1(2)sy6 and i have attempted to have a set of mac addresses to get a specific ip from dhcp. below is what shows on the bindings. 10.1.4.200 01e0.508b....
0 votes
1 answer
37 views

Scenarios in which a host (e.g. Debian) would update its ARP table [closed]

For security reasons, I'd like to know for which of the following scenarios would a host (Debian for example) update its ARP table: It receives a gratuitous ARP for IPs that are not in its ARP table ...
0 votes
1 answer
84 views

Too many mac addresses in a switch - Cisco Packet Tracer

The image of a network im refering to is above. In Cisco Packet Tracer after having used a command ping 192.168.1.3 from pc1 to pc3, when I check mac addresses in both SW1 and SW2 using show mac ...
0 votes
2 answers
210 views

How to get all the device information between two devices

I've two devices: My-PC and Another-PC. The two devices are connected to a switch, which is connected to main switch with-in the same LAN. My question is: how do I get all the device information ...
2 votes
5 answers
7k views

How does a router know the destination mac?

so if I send a packet from a host to another from the same network we know the mac address of both the source and destination. However if the receiver is in a remote network the destination mac ...
6 votes
6 answers
6k views

How to solve problem with two devices with the same MAC address, connected to the switch?

I have two devices with the same MAC address (don't ask why, I can't solve it by replacing those devices or modifying MACs) connected to one switch. Of course both of them get the same IP from DHCP ...
-1 votes
1 answer
35 views

ISP ARP tables and routing [closed]

So I'm Network+ certified and have a beginners understanding of how network communication works, my head starts to split a bit though when I think about how the information is actually communicated ...
0 votes
2 answers
150 views

If the destination MAC is changed every hop. When it arrives at the destination router, how will it know which device to deliver the packet to?

I learned that inside a packet there is information about the sender's public IP and MAC and the receiver's public IP and MAC, and that at each hop, the sender's and receiver's MAC are changed along ...
30 votes
4 answers
74k views

How does a switch learn a switch table?

Say the switch table is empty. If computer A sends a frame destined to computer B, the switch will broadcast asking who has the MAC address of B. What if C suddenly sends a frame to A? What is the ...
1 vote
1 answer
56 views

Can ELI/AAI/SAI addresses be Multicast?

In a slideshow by IEEE regarding the Structured Local Address Plan (SLAP), I saw the following table: SLAP local identifier SLAP Quadrant Z bit Y bit X bit M bit second hex digit ELI 01 1 0 1 0 A ...
0 votes
1 answer
72 views

Ethernet frame's source mac-address out of a port in an ARP request forwarded to an interconnected switch towards an end host

PC1 ----- (P1) SWITCH1 (P2) ----- (P2) SWITCH2 (P1) ----- PC2 Assume two network switches SWITCH1 and SWITCH2 are interconnected to each other through their ports P2 respectively present on each ...
0 votes
2 answers
387 views

Is it possible to extract the source and destination IP addresses from a MAC header/frame?

I asked a similar question on SO, but was directed to post it here. For original context, see this SO post. In short, I'm trying to extract the source and destination IP addresses of a received packet ...
0 votes
1 answer
168 views

Arp and flooding

it is my understanding that nodes are not aware of the mac address of other nodes they want to communicate with, when a frame is created to communicate node A with node B, the destination mac address ...
0 votes
2 answers
285 views

Is there a way to find all MAC addresses in an Ethernet network?

How can I find all MAC addresses connected to a LAN network? Is there a way or protocol to do this?
0 votes
3 answers
551 views

Is knowing MAC needed for talking to another device in same wifi network?

I have heard about ARP protocol for learning MAC address of other devices in a LAN for communicating with each other. However, I am bit confused about how it works in a typical infrastructure mode, ...
1 vote
0 answers
26 views

how do I fight/ protect and gather evidence if my router was copy Mac and my Mac was ported? [closed]

I learned recently that my devices including router had it's Mac address copied multiple times. I believe I'm going through a network hacking that uses the Mac addresses to drown my network services. ...
0 votes
0 answers
26 views

Why are connected switches not a good substitute for the network layer? [duplicate]

Unless I am missing something, because switches can be chained together, I am not sure why the network layer is needed. Theoretically, one can dedicate a frame to any MAC address, and assuming there ...
11 votes
2 answers
24k views

What are EUI-48 and EUI-64?

What are EUI-48 and EUI-64 addresses formed and used? Give me examples. What are MA-L, MA-S and MA-M assignments? I have read https://standards.ieee.org/develop/regauth/tut/eui48.pdf and https://...
4 votes
1 answer
92 views

What's the differences between sticky-config MAC & sticky MAC on Huawei SW?

In Port-security configuration, port-security mac-address sticky-config xxxx-xxxx-xxx vlan x port-security mac-address sticky xxxx-xxxx-xxx vlan x 1.All of them do not disappear after SW restarting. ...
2 votes
3 answers
251 views

What does a modem actually know?

In a given setup: -> device 1 modem -> router -| -> device 2 Device 1 is wired and Device 2 is wireless. Does modem know the MAC addresses of devices 1 &...
1 vote
1 answer
293 views

What is PPP and why does it not have a MAC address?

I just wanted clarification on what exactly PPP is and why it does not have a MAC address due to having seen that under a response to a question of how routers transverse packets to their destinations....
1 vote
3 answers
7k views

How do routers traverse packets to their destination?

Sorry in advance for such a noob set of questions. I understand that when set with the task of sending a packet to its destination, a computer first checks that the IP address of the destination is ...
0 votes
1 answer
980 views

Sharing same IP address inside LAN? [duplicate]

Q: if 2 devices A and B share same ip address in LAN, can device A retrive all messages whose destination is device B? I think this depends on how the LAN is configured. If it's wireless then device A ...
0 votes
0 answers
16 views

Are ARP messages always used for the process of "Flooding" even when layer-3 is not involved? [duplicate]

I'm new to learning networking so please bear with me. I've learned that ARP messages and flooding are used to find mac addresses when IP addresses are involved. I've learned that when the mac address ...
0 votes
0 answers
10 views

How do devices on a network communicate when they are only connected through a router? [duplicate]

This is in my router's routing table: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.1.0 0.0.0.0 255.255.255.0 U 0 ...
0 votes
2 answers
171 views

Failover with sticky MAC address on network switch

Introduction: I am configuring a server to have two ethernet ports (one as primary, the other is redundant) connected to two different switches. In the switches, I enabled the sticky MAC address and ...
0 votes
2 answers
198 views

What's the difference between host routes and network routes for layer 2 destination selection?

This problem usually occurs with servers, but the question itself is about network. When I have a gateway with 10.1.1.1 and an interface with /24 network, the network routes are automatically ...
0 votes
1 answer
312 views

trying to ping 192.168.2.2 from 192.168.1.1 pcs

im trying to ping pc2 from pc0 and it doesn't work can anyone help tell me why? pc0 is 192.168.1.1/24 and pc2 is 192.168.2.2/24. The port connecting switch 0 is 192.168.1.100/24 and the port ...
0 votes
2 answers
89 views

Where does a host save its IP address?

While building a particular packet to be sent across or outside the network, the host, at a certain point, needs to specify the MAC address of the interface through which the packet is going to be ...
1 vote
3 answers
142 views

dynamic mac address added all hosts through the Do1Q tunnel

we have a nexus switch, we configure two customer ports in different switches with (mode Dot1Q tunnel) as all traffic must have two VLAN tags, an inner tag, and an outer tag, in our network, we ...
1 vote
1 answer
416 views

Why specify the address of the default gateway in the routing table?

I’m struggling to understand the need of specifying the default gateway in the host’s routing table. When a host is building a frame to be sent, it needs to specify two MAC addresses; one for the ...
1 vote
1 answer
84 views

Does the host need to access the routing table to know if the destination IP address exists in the same network?

It is said that, in the process of building a frame, the host checks if the destination IP address exists in the same network. My question is concerning how the host performs this check. Does the host ...
0 votes
1 answer
248 views

Why does the show arp returns a different IP than the PC's gateway on the Switch

I have a PC connected to a switch connected to a router : why does the show arp returns a different IP than the PC's gateway on the Switch ? : PC $ arp -a | grep -w gateway gateway (172.16.15.1) at 00:...
1 vote
0 answers
17 views

Does a router need ARP to send data to router in anther netwrk, it already has the IP address of the interface right?why does it need the MAC address? [duplicate]

i am studying off this https://www.practicalnetworking.net/series/packet-traveling/key-players/#arp but my question is if ip address is for end to end communication , how is the end to end happening ...
3 votes
2 answers
3k views

Show port on Cisco switch that mac address is being dropped on

We use ISE to handle port security on our switches. When I see that there is a mac address being dropped by the switch it doesn't show what interface this mac is patched into. #show mac address-table (...
0 votes
3 answers
320 views

Lost the Static IP/network settings of a device

We have a physical device (lab instrument) that we can only connect to via ethernet. Unfortunately a static IP was set with network settings and these settings has been lost. We connected our computer ...
1 vote
1 answer
262 views

MAC OUI in Bits 3 to 24

One networks basics course the statement was made by lecturer for OUI (Organizational Unique Identifier) to be carried in MAC-address Bits 3 to 24. I wonder where the start bit number 3 from? It is ...
1 vote
1 answer
196 views

What happens if the layer 2 destination MAC address mismatches?

I was wondering, what happens if I send a packet with layer 2 destination (say 1ebf) different that what will receive it, lets say a router (mac 22ff) recieves it. Will it drop the packet? Or ...
7 votes
4 answers
14k views

Is it possible to perform a Layer 2 (MAC address) traceroute?

I understand the difference between layer2 & layer3 and MAC & IP. I understand address resolution protocol, etc. But is there any way to do a traceroute that will show Layer 2 information? For ...
1 vote
1 answer
896 views

ARP table updated when receive message

I'm studying networking and I have a question about when an ARP table should update. Consider this scenario: Host A has the MAC address of host B in its ARP table. Host B's ARP table is empty. ...
3 votes
3 answers
1k views

Can you send data in LAN without an IP?

From What I know, IPs are used to communicate b/w two different networks say LAN1 and LAN2... and MACs are used to communicate within a LAN.. I think this because my instructor says that Hubs and ...
0 votes
1 answer
2k views

How to simulate Mac flooding attack in Cisco Packet Tracer?

I'm trying to see effectiveness of port security on Cisco switches using simulations in Packet Tracer.but first I need to run some Mac flooding address attacks on switches in Packet Tracer. Can anyone ...
1 vote
1 answer
131 views

Does RSTP also maintain correct mac table entries?

I've got 4 switches connected in a circle and they all run RSTP. Lets assume the following: switch A (root bridge) ------- switch D | | | ...
0 votes
0 answers
23 views

What is the difference between a private IP and a MAC address? [duplicate]

I am taking a course preparing me for the Network+ certification. I wanted to know what the purpose of a private IP is when a MAC address exists. From what I understand, the MAC address is used to ...
0 votes
1 answer
62 views

What are the IP/MAC addresses of requests between 2 different subnets? [closed]

Assume that networks 172.15.10.0/24 and 172.15.11.0/24 are connected through a router with interfaces 172.15.10.254 (MAC3) and 172.15.11.253 (MAC4). If host A sends a packet through its network ...
0 votes
1 answer
575 views

Unknown cause of disappearing CAM table entry and unicast flooding

Posting this in response to the closed question: Network flooding without ff-ff-ff-ff-ff-ff (layer 2 broadcast) MAC address in destination? I have a network that is experiencing the following problem: ...
2 votes
3 answers
6k views

What is the relationship between the IP address and MAC address?

I own a MAC address and I want to know from it, the IP address.
8 votes
6 answers
5k views

How Does A Layer 2 Switch Differentiate Between Different Networks?

I know that different IP-based networks can be connected to the same layer-2 switch. and I know each network's nodes can communicate just fine, however, no normal traffic can occur between two nodes ...
1 vote
3 answers
579 views

Why switch uses Mac address during implementation of spanning tree protocol (STP)?

We know that layer2 switch doesn't use Mac address ,uses only certain port number to accept the frame. But I have been read on book as well as internet that uses Mac address to find spanning tree for ...
3 votes
2 answers
2k views

Mobile cellular Networks (GSM, LTE, 5G, ...) and MAC addresses

We've been provided with a new firmware for our telematics units, which connects to the Internet via a VPN provided by a mobile carrier; since this new firmware release, we've noticed that each and ...

1
2 3 4 5
9