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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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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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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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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368 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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703 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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327 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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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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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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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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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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807 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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87 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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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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259 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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109 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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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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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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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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195 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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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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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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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 to 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 of ...
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670 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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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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313 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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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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Can I use nmap be use 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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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?

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 -> ??
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Changing MAC address on the Fly on old kernel 2.6.x

I'm doing some research on old kernels and running the following on 2.6.7 or 2.6.8 gives a resource busy error. But on 2.6.28 the command works as expected. How would I determine which kernel allowed ...
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Does Mac address base restriction is possible over Internet?

I want to restrict the access into my server on MAC Address base over internet... does it possible??? or there any other way of restriction over internet instead of IP address possible?? (My users ...
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bad switchs duplicate my ip

I had a large area LAN. There were many switch and AP on it, then somehow I couldn't ping my servers, and it's said that the IP was duplicated. I use arpwatch and found out that one of the switch ...
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What does the MAC setting on an interface do to the ability to transmit frames?

I'm told that an interface can transmit a frame no matter what the OS has set for the interface's MAC. I'm also under the impression this is how VMs do host-bridging. If that is so, then what uses the ...
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What does ifconfig promisc mode do, or promiscuous mode in general?

This is what man ifconfig has to say about it. [-]promisc Enable or disable the promiscuous mode of the interface. If selected, all packets on the network will be received by the ...
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In Ubuntu, ensure that the same NIC gets assigned the same interface each time it comes up

I'm running an Ubuntu 9.10 server that has multiple NICs in it. I'd like to make sure that each time the kernel boots up, the NIC with MAC address 01:23:45:67:89:ab gets assigned to eth0 and the one ...
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Can one identify the MAC addresses participating in a wireless network?

Specifically I'm trying to track a portable device by MAC; it may be participating in either an open 802.11b network or one with WPA. Is it possible to monitor these networks for the presence of the ...
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Can I get the Network Adapter type (wired / wireless) from its MAC address?

I know I can get the card manufacturer ID from the MAC address, what about the "type" ?
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Will MAC filtering increase Wifi security?

I've always thought that you should enable MAC filtering to increase Wifi security (in addition to using WPA2). Now I've found this article (Wireless LAN security hall of shame) that says MAC ...
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1answer
232 views

Exchange server (apparently) changing MAC address

Occasionally, I stop being able to access our Exchange server from my PC. Just my PC - everyone else carries on without incident, but I can't ping the Exchange box, log in with Outlook or get to the ...
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Is there a way to determine if a certain MAC address is on the local network from a Synology Cubestation, which doesn't have arp?

I have a bit of a strange problem, I am trying to determine if a certain MAC address (my xbox 360) is on the network (i.e. on) The problem is i'm doing it from my Synology Cubestation, which is a ...
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Odd traffic behavior of statically entered mac addresses over cisco 3750 vlans

At my workplace we use cisco switches to a implement a custom traffic delivery mechanism at layer 2. Custom software puts specific destination macs on ethernet frames and vlans segregate the traffic ...
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What security problems are caused by public MAC address knowledge?

What types of attacks are made possible or worse by having knowledge of a target computer's MAC address? I am planning on using a type 1 UUID generator that includes the generating computer's MAC ...
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cloning mac address of physical server converted into vmware server

We've recently converted a physical Windows Server 2003 into vmware using P2V. However, one of the pieces of software on the 2003 machine are still looking for the old server's network MAC address in ...
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Assign DHCP IPs for specific MAC prefixes

I'm running a ISC DHCPd server for my network serving a number of subnets. One of the things I would like to do is assign a specific range of IPs to hosts with a common MAC prefix (ex. 00:01:02). ...