A Media Access Control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment.

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Redirect traffic on port 80 into apache for unknown macs, and into squid for some macs

I have a linux box behaving like a router that handles two network interfaces: eth0 for internet and eth1 for LAN. I set up iptables in order to redirect all the web traffic coming by the LAN into a ...
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70 views

Possible MAC conflict in ESX

I have two virtual machines that are 10.1.1.10 and 10.1.1.20 in an ESX. I try to access theses machines by another network 192.168.1.0/24. The problem is that when I can ping one machine, I can not ...
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432 views

Broadcom NetXtreme II GigE Teaming Does Not Use Unique MAC, Causing Collisions

I currently have a new Dell server on my local (inside) network that I have setup to use three of the four nics to create a team. Examples below. NIC_1 - mac: 000000000001 - ip: n/a NIC_2 - mac: ...
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89 views

MAC Addresses (in devices) [closed]

In what type of hardware are MAC addresses used besides routers? For example, could a MAC address be in printer or in a mobile phone? Yes, I am talking about Ethernet MAC addresses. Can you please ...
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4answers
2k views

Cisco Switch: trigger mac-address table update

If I run show mac-address-table dynamic I get a bunch of mac addresses on that table. But due to the aging parameter, I don't see the mac addresses of all possible devices on the network that come ...
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1answer
677 views

Same MAC but different IP on router [closed]

If a device has same mac address but different IP on home router, is this some sort of error or hacking? What is going on? I can't attach a pic so I've listed below. Computer name for second doesn't ...
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2answers
415 views

clone ip and mac addr on wlan

what will happen if i clone another pc on a wlan network? consider the following scenario. PC1(victim) mac1 ip1 PC2(attacker) mac2 ip2. I set mac2 = mac1 and ip2 = ip1 i ran the following ...
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618 views

Solaris doesn't know which MAC address to use to send an UDP multicast message

I have a pair of Solaris 10 boxes which are supposed to send multicast UDP packets to a group of hosts. One of them works just fine, whereas the other one does not. The problem with the second ...
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1answer
373 views

Switch CAM table and ARP messages

When the switch CAM table is empty and it receives an ARP message, does it add to the CAM table the source MAC address ? In Packet Tracer I saw that it does add it, but I read in some book that the ...
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3answers
8k views

Duplicate MAC address on the same LAN possible?

Let's say someone is on the same network as me and spoofs their MAC address to match mine: Is this possible? Can two or more clients with the same MAC address be on the same network at the same time ...
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1answer
383 views

Cisco switch:change mac type from dynamic to static in console

How to change mac from static to dynamic in mac-address-table (switch)?I find this official source but still not understand what options I must choose. Something like this: switch(config)# ...
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88 views

how to block mac address with portsentry

I use portsentry to block ip address who trying to scanning. Now how do I want to block mac address who trying to scanning. Can I use portsentry, or possibly other tools?
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4answers
405 views

Newbie questions on MAC and high availability failovers

I am reading about High Availability and I can not understand the following I read: On failover the primary IP migrates to the backup server BUT so must the MAC address. Specifically I read that ...
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1answer
109 views

MAC and IP address text-identicon as avatar

I would like to create something like identicons but not with images but with a unique word for each IP-Addresses and MAC-Addresses. create an easy to remember alias for a mac address, that is unique ...
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2answers
332 views

Why do we need logical addressing [duplicate]

Possible Duplicate: Why couldn’t MAC addresses be used instead of IPv4|6 for networking? If physical address or Mac address is unique why do we need logical addressing? This because ...
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2answers
1k views

What is the Cisco iOS (CLI) command to display a WAP's Radio MAC address?

I can't believe I'm unable to find this with teh g00glez or by RTFMing, but does anyone know how to display the MAC address of a Cisco WAP's Radio (wifi connection) from the command line? show ...
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2answers
674 views

Connectivity issues when setting guest MAC to the same as the host MAC on ESXi 5

I am using VMWare ESXi 5. The ESXi 5 host has a NIC with the MAC XXXX:XXXX:XXXX I have created a console port for that card. I have added a new guest named COMP and manually assigned the MAC address ...
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2answers
202 views

Find IP address from a MAC address

Is there anyway to find the IP address of a MAC address using a command? I was thinking something like arping might work but can't seem to find much information on it.
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2k views

Ping server NETBIOS name returns wrong IP and “Destination host unreachable”

Problem server is Windows 2008 R2 VM running on VMWare ESXi 4 host. Single network adapter manually assigned single IP address (192.168.1.11). When I ping the server from any other network computer, ...
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13answers
25k views

Why couldn't MAC addresses be used instead of IPv4|6 for networking? [closed]

I am reading up on TCP/IP and other related protocols and technologies. MAC addresses are described as being (reasonably :) unique, and as having a large possibility space (several hundred trillions), ...
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1answer
75 views

How to fix Parallels Management Node if DHCP server filters MAC address

I'm evaluating Parallels Server on Mac OS X  Lion Server, and during installation it sets up a "Management Node" VM for managing the other VMs. The problem is that my DHCP server is filtering MAC ...
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2answers
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How do I find out which physical port my ethersvi MAC address corresponds to on a Cisco switch?

I'm doing a layer2 network map (my first) and this is the first virtual mac I've encountered. From the mac address table of switch1, I have VLAN 1 6416.8d98.52c0 DYNAMIC Te0/1 and on the ...
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135 views

How does a device search for available wifi networks? [closed]

Say you have a wifi device (D) and a wifi router (R) that have never shared radio waves before, and are within range. How does D discover that R exists? Does R constantly broadcast a message with its ...
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Can I create a pf rule involving MAC address instead of IP?

The title is self explanatory. I want to create rules in pf running on OpenBSD 4.9 for perticular MAC address, something like pass in on eth0 from mac 00:04:34:5f:34:33 to mac 34:32:34:06:5e:22 I ...
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474 views

Get the MAC addresses of all the machines connected to a LAN when NO machines have got an IP address yet

Here is the real scenario. I have say 4 machines not having any IP address yet connected to a switch. In one of the machines (OS=CentOS), I would install a DHCP server and would provide the other ...
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2answers
914 views

Tie SSH key with MAC address

I have a ubuntu server which I scp files to often. It is setup for password-less authentication using a key I have on the server. Is it possible to tie a mac address to the key so that only my client ...
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2answers
3k views

ISP login, MAC spoofing, WiFi and multiple devices

I have a Tikona Digital Broadband (WiMax based) Internet Connection which allows limited number of devices to be connected at a time and also requires that the users login with username and password ...
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1answer
86 views

Is it possible to distinguish traffic from different computers from behind a router?

The mac address would be that of the router, I presume. But could I distinguish the ip addresses of the computers behind the router, or could I only see a global ip address that belongs to the router? ...
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1k views

Using Ipset and Iptables for MAC address filtering

I use MAC address filtering on my Linux router. Here is what I have done: iptables -A INPUT -i eth5 -m mac --mac-source 00:07:e9:84:2b:99 -j RETURN #User: Someuser iptables -A INPUT -i eth5 -j DROP ...
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2answers
525 views

How can I separate a VMWare Server from the host's MAC Address on my router?

I'm running a Debian LAMP Server in VMWare Player, using a bridged connection. However, on my router the VM is showing up with the same MAC Address... therefore I can't set the VM to a static ...
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Look up manufacturer based on Mac Address?

I want to incorporate into a piece of software the ability to look up a manufacturer based on a mac address. By googling "mac address lookup" and similar, I have noticed several websites that make ...
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156 views

Cloning IP address and/or MAC address for server fail-over

I am currently providing some web applications to my customers (apache/php/mysql on Windows server). I'm looking to provide some sort of fail-over server in the case my server has a hardware failure. ...
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9k views

Query a Windows DHCP server : find MAC from hostname

From my computer, I want to query my DHCP server to find a specific mac adress. I want to enter the hostname to search, and getting back the Mac address. Something like : netsh dhcp server scope ...
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333 views

Assign arbitrary MAC address in VirtualBox VM

Is it possible to assign an arbitrary MAC address to an VirtualBox virtual machine instance? This answer suggests that it is only possible to generate MAC addresses where the most significant byte is ...
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4k views

NIC Teaming with Broadcom on HyperV 2008 R2

I have a HyperV cluster made up of 3 hosts. Each host is connected to both of my Nexus 5548 switches running in an etherchannel. LACP on the switch and NIC teaming using Broadcom 802.3ad on the server ...
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Is bonding mode=5 a solution against MAC flapping?

There is two are interconnected Cisco WS-2950T. By the one GBIC port on first switch connected a first NIC of bonding interface, and by the one GBIC port on second switch connected a second NIC of ...
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1answer
3k views

Ubuntu Linux - two interfaces, same subnet, different vlan - MAC/ARP issues

I'm attempting to setup a server that needs to have interfaces on the same IP subnet, but different VLANs: eth1.102 Link encap:Ethernet HWaddr 00:50:56:b1:00:0f inet addr:10.1.1.6 ...
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1answer
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Managed Ethernet switch per-port MAC address translation?

Just a shot in the dark here, but I thought I'd ask in case anyone has some ideas: I've got a testing scenario where some (GUI-less/embedded) IPv6 devices are going to be temporarily plugged into the ...
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2answers
1k views

Using DHCP with Multi-Homed NICs

I am trying to steer away from our current manual addressing system and embrace the decades-old wonder of DHCP. In our domain and even at my home network DHCP is great - I can use address reservations ...
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2answers
1k views

MAC Address of device when turned off?

Is it possible to get a list of MAC addresses of devices connected to a network, even though the device is currently turned off? The device has power so I could do a wake-on-lan. I'm trying to get ...
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651 views

MAC addresses on dual-NIC mainboards

Here's a weird problem. We've got a number of devices with dual-NIC mainboards. Some are Realtek NICs, which suck. Some are Intel e1000s, which don't. I've just noticed on 2 machines, one is an ...
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3answers
579 views

On CentOS 4.5, How to Masquerade a connection using MAC address?

Currently we give Internet access using ip address in our firewall script as follows iptables -t nat -A POSTROUNTING -s 192.168.1.40 -j MASQUERADE But we have noticed that some guys steal these ...
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1k views

Get client's MAC address when connecting with SSH

I want to get the MAC address of every machine that connects via SSH to my server. Is this possible? If yes, can you provide me some references? Thank you in advance!
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218 views

About the MAC table on switches?

I'm learning the network basics at my university this semester. I had a question on the mid-term exam and unfortunately ,I answered it wrong. I have a final exam about an hour from now, and I still ...
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3answers
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Ethernet frames: what are the source and destination MAC addresses?

Imagine you have some network configured like this +-----+ +------+ +------+ +-----+ |comp.|---|bridge|---|router|---|comp.| | A |---| B |---| C |---| D | +-----+ +------+ ^ ...
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How can I change the MAC address of a network bridge in Windows?

I use DHCP reservation rather than static IP for convenience, and that relies on the MAC address of my computer. I recently bridged my main adapter with my VirtualBox adapter. When things stopped ...
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597 views

Counting traffic to destination MAC address using ebtables/iptables

I would like to be able to count the number of bytes going to a given MAC address using iptables or ebtables or some other linux utility. I have tried looking at the byte counts in ebtables but they ...
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3answers
730 views

Why need to send ARP to ask for MAC address when IP address is already unique? [closed]

In the usual networks, since every host has a unique IP address recognised among the stations in the network, why is a MAC address still necessary? Suppose a station A wants to send to Station B. ...
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Can I get the original MAC address after it has been changed?

I am using some linux machines that have had their MAC address changed. I would like to be able to read it back with a shell script. Is the original MAC address stored anywhere except the sticker on ...
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4answers
155 views

Linux - Is there a way to determine what mac addresses an interface has seen traffic from?

Yes, I know about ARP but that relies somewhat on IP layer connectivity in that the remote system must be configured with an IP on a recognized subnet. Is there any way to just dump off what mac ...