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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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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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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731 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
625 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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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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222 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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1answer
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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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2answers
683 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
973 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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2answers
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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
170 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 ...
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1answer
1k views

Set Mac Address in QEMU/KVM properties file

I'm trying to set the mac address for my virtual machine in the virtual machine properties file. The properties file '102.conf' currently looks like this: name: vm1.mydomain.com bootdisk: ide0 ...
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5answers
4k views

How do I MAC filter with DHCP server

I want to Only allow certain MAC addresses to get a IP from my DHCP server, currently I use dnsmasq and I rather not change dhcp server but I'm open to other software aswell. However, I need to be ...
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1answer
241 views

Mac address filtering radius server

I would like to use the radius server on mac os x server (10.6.8) to allow users to access wireless. However the restriction i would like to use is Mac address filtering. Is this possible? how can i ...
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5answers
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how to generate a random MAC address from the Linux command line

How do I generate a random MAC address from the Linux command line? I search for a solution that only requires standard tools commonly found on the Linux command line. The MAC address will be used ...
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1answer
2k views

IP address conflict with MAC address 00:00:00:00:00:00

One of our Windows 2003 R2 ISA firewall servers recently had a 1-hour spell of intermittent connectivity to our Internet WAN connection, which was fixed after disabling then re-enabling the network ...
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4answers
589 views

Is there a tool like 'route' in Linux to configure the forwarding entry (dst mac address --> interface)

I have a problem in configuring the forwarding table in Linux. We call IP tables for routing table in layer 3, MAC tables for forwarding table in layer 2. Now I want to add an entry in forwarding ...
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1answer
447 views

raisecom get vlan macs by snmp

I'm, trying to get mac addresses from switches in a network. For that i'm using snmp calls with these oids: (like in this manual) .1.3.6.1.2.1.17.4.3.1.1, .1.3.6.1.2.1.17.4.3.1.2. But i have a problem ...
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1answer
838 views

Want to wake up a computer using wake on lan but don't know mac

A computer I only have remote access to is shutdown, but it has been powered on in the last 2 hours.. I have access to another PC on the same LAN, will the target computer's MAC address persist ...
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1answer
353 views

Valid MAC-Address with a zero-byte at last position?

is it possible that a valid MAC-Address has a empty (zero) byte at the last possition? For Example: Byte 1 = 00 Byte 2 = 26 Byte 3 = B9 Byte 4 = 13 Byte 5 = 7B Byte 6 = 00
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1answer
2k views

Windows 7 Machines do not take reserved IP address from DHCP

I have NETGEAR router - WGR614 V6 and have mixed network of Linux machines and windows PCs. I use the router's in-built DHCP. I use 'Address Reservation' feature of the router to reserve IPs based on ...
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2answers
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Deny Static IP Assignments

I am currently using a SonicWall Pro 2040 with DHCP enabled, but only with static IPs mapped to specific MAC addresses. There is no dynamic IP scope being used. Currently, no DHCP request will resolve ...
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3answers
483 views

Limiting network access by MAC address and what else?

How can I limit the network access to a physical network from outside computers being plugged in? I know MAC filtering is one way, VPN is another - but it's not going to be used, so what else?
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Is a Network Switch IP-Aware?

I have some very trivial basic questions about networking, but I find varying information on that, so I just wanted to settle this. As far as I understand a Network Switch handles traffic ...
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2answers
935 views

Manually set IPv6 neighbor's MAC address in Mikrotik's RouterOS

I have an interesting problem. An ISP of ours started providing native IPv6 on their network. They provided us with a /56 prefix and a /126 linking segment (::1 being their endpoint and ::2 being ...
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1answer
906 views

Assign DHCP IPs for specific MAC prefixes on Windows Server 2008 R2

I'm running Windows Server 2008 R2 for my DHCP server. We are about to switch over to a VoIP system and Cisco VoIP phones. I would like to assign a specific range of IPs to these phones which will ...
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1answer
88 views

What would cause a Windows 2008 server to switch destination MACs in the middle of a TCP session?

My Windows 2008 server started a TCP session talking to one destination mac address, but in the middle of the TCP session started sending packets to another destination mac address and then eventually ...
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4answers
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What happens if two computers have the same MAC?

Possible Duplicate: Can duplicate MAC addresses on same LAN cause trouble? What happens to network traffic on a switched LAN if two devices have the same MAC (probably because one is ...
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263 views

Hash function in shell that could be used for an ssh port from (say) hwaddr of eth0

I have a growing number of remote machines that ssh home and setup a connection to allow subsequent access via tunnel so I can get into them for maintenance. Currently, I must manually configure ...
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1answer
110 views

Packets for internal network addresses get gateway's MAC

i have the weird problem that certain incoming packets get forwarded to my internal netwerk with the right internal IP but when using wireshark i see that the MAC address is set to the routers default ...
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0answers
222 views

dhcpd.conf rule-based mapping

We have ~100 physical nodes which can host a large number of VMs apiece. We need to set up dhcpd on one machine to distribute addresses in a predictable fashion based on MAC address. We'd like to go ...
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DHCPDISCOVER requests from an off-by-one MAC address

In a Linux DHCP server I'm getting a bunch of these log lines: dhcpd: DHCPDISCOVER from 00:30:48:fe:5c:9c via eth1: network 192.168.2.0/24: no free leases I don't have any machines with ...
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4answers
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multiple MAC addresses on one physical network interface (linux)

Simple question: How can I setup multiple MAC addresses on one physical network interface (linux)? Why? My ISP is checking ip<->mac on GW and I d like to route traffic through my "linuxbox" and ...
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Attempting to find a device from MAC/IP

I have had a look through the related questions for this issue and was not able to pick up a solid answer. I'm getting closer via my poor use of google-fu, but I'd like to ask you guys as well (I'd ...
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3answers
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How does VMWare generate unique MAC addresses?

I'm looking to build a series of VMWare Virtual Machines as my client needs them. The hostnames and IPs have been pre-assigned. But I'm going to need to add rules to our switches for each host's MAC ...
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209 views

MAC spoofing - keeping the connection alive

Is it possible to keep a connection alive, while spoofing/changing the MAC address of your own network adapter (especially wlan adapter), without needing to re-authenticate against 802.1X ...
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2answers
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list known mac-addresses on Dell PowerConnect 5324

I have a Dell PowerConnect 5324 (SW version: 2.0.1.3) which I hardly ever use. I need to list out the mac-addresses it sees on certain ports, such as g23. I have fooled around with the cli and done ...
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Can I translate the MAC address to the exact ethernet card model?

I know that if I have the mac address I can find the vendor of the card but is it possible to find the exact model?
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VirtualBox Import & Same Mac Address

Exported Virtual Box VM (CentOS 5.5 with Guest Additions Installed) - Success Imported CentOS VM Successfully on another Windows Machine via Windows Batch Problem : VM After Import retains the same ...
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1answer
401 views

VMware Converter MAC Adress

I want to convert a running machine to VMware ESXi with VMware Converter, but it assigns a random MAC address to destination virtual machine. However, in our network, port security and static arp ...
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1answer
2k views

Assign computers to specific VLANs with Dell PowerConnect 3524/6224

Our network consists of a number of Dell PowerConnect switches. 1 x 6224 (core switch) 5 x 3524 cabinet switches. We are using VLANs, to segregate different classes of systems. This was first ...
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How to discover the MAC address of machines in a network?

How do I discover the MAC address of machines in a network? I need to discover the machines that are available just with only BIOS installed (no operating system). And I need to find the MAC address ...
5
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4answers
745 views

MAC address spoofing - why doesn't this work?

So I'm in a new job, and they're pretty draconian about their network, hardware, and OS security. :-( I'm a web developer, but am forced to use IE7 for development simply because they don't want ...
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3answers
7k views

Cisco IOS router MAC or IP address filtering

I'm trying to filter a specific device from my network. Either MAC or IP address filtering would do the trick, but I have trouble finding the exact Cisco IOS commands to use. My router is a Cisco 870 ...
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1answer
316 views

Gateway - Understanding packet details (IP and MAC addresses)

I'm learning the Cisco CCNA material, and most of it is completely new to me. I'm currently learning about how source and destination IP addresses are defined in the IP packet header and the source ...
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4answers
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MAC address filtering in Linux

I'm a new system administrator of an existing Linux network. Apparently there is MAC address filtering there. How could I allow a specific MAC to connect to the network? The INPUT, FORWARD and OUTPUT ...
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4answers
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Can I use nmap to discover IPs and mac addresses?

When I need to locate the IPs of devices by their mac address on a Windows system, I normally use Advanced IP Scanner (from radmin.com) to scan the network, then I use arp -a to list the mac ...
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1answer
265 views

How to prevent response to who-has requests on virtual eth interface?

we use small embedded X86 linux servers equipped with a single physical ethernet port as a gateway for an IP video surveillance application. Each downstream IP cam is mapped to a separate virtual IP ...
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Is is possible to to make several different IP point to the same machine? [closed]

If the answer is possible,how? DNS is not for this kind of job,obviously. UPDATE Can someone answer this question: domain name : IP -> DNS; IP : Mac -> ??