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 create DHCP reservations with long hardware address?

DHCP is managed by a Windows 2008r2 server. I want to convert a lease into a reservation so the IP will be fixed. Normally, I create a reservation based on the assigned IP address, and when the lease ...
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19 views

How do I properly configure KVM

I have a remote dedicated server on which I have installed KVM. When trying to create my first virtual machine I am unable to ssh to the machine. I assumed that I needed another ip address so I ...
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32 views

Assign more than one IP Address to the same MAC Address on Linux ISC-DHCP Server

I have the following question: One Linux DHCP server in pool mode, because of the step of fabrication, all the products have the same MAC Address that is changed at end of line, the boards use ...
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15 views

ARP cache getting null mac over a bridge

I have an interface eno1 and a bridge br0 $ ifconfig br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.250.53 netmask 255.255.255.0 broadcast 192.168.250.255 ...
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How can a WiFi router recognize MAC address change of a connected device? [migrated]

My teen son and I are playing a hacking game. I've installed an WiFi router with parental controls, MAC filtering, VPN, etc. I block Internet for him, he tries to break out of the cage (for now I'm ...
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3answers
43 views

Obtain MAC address of remote, unconfigured device?

I have a device that goes on the network. I need it's MAC address. There is no label on it. How do I do that? I have no access to the device itself. I can power it on and plug it in to a switch ...
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1answer
22 views

Packetfence & Aruba

I have a fresh install of a PacketFence (PF) server. Also, I have an Aruba networks AccessPoint (API-205), which I am using to send the users to the Captive Portal in PF. But the captive portal ...
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23 views

Cannot find a device attached to network

My work has a wireless alarm system installed, and we recently got a wireless camera to add to it (made by the same company, it simply plug-n-plays). The alarm system uses a small router like device ...
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2answers
29 views

iptables DNAT broadcast address

I'm having trouble using iptables to change the destination address of a broadcast packet. I have read several places that iptables/Linux won't forward broadcast packets, so I'm looking for ...
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87 views

iptables is occasionally logging MAC addresses. Why?

I have logging enabled on specific iptables packet drops. The rules I'm using are IP/port related only and this is what I can easily see in the logs, however occasionally I do get MAC address ...
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1answer
49 views

Spoofing a duplicate MAC address on an interface not connecting to the network where the original MAC is

I'm trying to run a PHP project on a test server. The project uses an internal framework that has been modified so it will only run on the production server by checking the MAC address in eth0, and ...
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18 views

How to set a specific mac addres in docker

I'm trying to set a specific mac address in docker using the following command but it's not working docker run --lxc-conf="lxc.network.hwaddr=ec:g6:bb:98:9c:d3" -i -t 0d14 anything wrong with the ...
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48 views

DNS propagation to new box with upgraded CentOS using same IP

I am having trouble with a DNS Configuration. I've had a CentOS 6 server serving five sites up for a few years. I need to upgrade to CentOS 7 for PCI compliance. I bought a new box and left the old ...
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1answer
66 views

What will happen in a network if multiple devices have the same MAC address? [closed]

What will happen in something like a wifi connection where different laptops are set with the same MAC address . To make it more interesting what will happen if there are multiple devices with same ...
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1answer
84 views

How to prevent users from scanning the network

in my network many peoples spoof mac address, they get mac adresses of online users by scanning the network or the ip address range and using wireshark they get easily any mac address so how to ...
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1answer
168 views

Using the same mac address on the same network at different times on two devices

If I was to use the same mac address as another device on the same network (wifi), at different times (one after the other). Would the devices for the network experience any problems, glitches or ...
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31 views

Server is using MAC address of eth1 when connecting to eth0?

I have a server with 10.10.1.1 on eth0 and 10.10.2.1 on eth1. The routing table has 10.10.1.254 as it's default gateway. There's a freenas box on 10.10.1.200 which keeps reporting that 10.10.1.1 has ...
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50 views

Changing source MAC address of routed packets

I have linux box with one network interface and IP forwarding enabled. Let's say my IP address is 192.168.1.1 and MAC is 11:11:11:11:11:11. When a packet which is not targeted for my host arrives, it ...
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131 views

Duplicate MAC address in VMware deploying from template

I am trying to deploy a VM from a template. This template has been used dozens of times before; nothing special. The problem is that seemingly out of nowhere when I deploy a VM, it's giving it the ...
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24 views

Configuring additional static IP for Guest Machine

I am trying to bind my Guest machine to respond on my second public IP address. Sometimes it works automatically by DHCP just by configuring my MAC address, sometimes it doesn't work at all. All I ...
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1answer
323 views

Cisco switch: Trunk port MAC address disppearing from MAC address table

I have users complaining of slowness on their machines but we can't find anything specific (ping tests, etc). I'm trying to rule out the connection between the switch they're plugged into (3560) and ...
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2answers
133 views

Is the MAC address of the physical host used in a virtual environment?

In an environment with virtual servers, is the MAC address used to communicate, the MAC address of the physical host, or the MAC address of the virtual adapters. If it's is the virtual MAC address how ...
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burnt Switches connected directly to the internet

We got a setup with a switch between the cable modem/bridge and the two router ports. We burn this switch every 6 months, and it has to be replaced. Symptoms are heavy packet loss or in general very ...
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126 views

Can ISC-DHCP bind to Option 82 rather than Mac Addresses?

We use option 82 information to limit leases presently in ISC-DHCP using a spawn with statement for our billing subclass. This keeps a single household/business from obtaining more leases than they ...
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1answer
91 views

calculate reserved ip address based on mac address

Is it possible to calculate ip address based on mac address for isc-dhcp server? For example: 'aa:aa:aa:aa:aa:x' => '10.10.10.x' I have following in dhcpd.conf: subnet 10.10.10.0 netmask ...
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1answer
126 views

Virtual interfaces with different MAC addresses

I try to figure out how to set up two logical network interfaces (at one physical interface) with separate MAC addresses on a Linux machine. My first attempt was to use macvlan which seemed to work ...
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53 views

The Router Mac Address [closed]

Some sites can get the mac address of my network interface bu using cookies or java script ! but can they get my router mac address ?
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83 views

Polycom VOIP phone seems to mask the secondary device's MAC address from a Cisco switch

When I have a Polycom VOIP phone plugged into a Cisco switch and a laptop plugged into the Polycom phone I get the following. 1) The phone goes into the voice VLAN as expected. 2) The laptop goes ...
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2answers
122 views

Is there a way to query all the mac addresses in a network?

I know this question was flagged "off-topic" and "non-professional", but when creating a gateway or IDS, this might be quite relevant. Also, Google finds nothing usable... There is a thing called ...
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1answer
617 views

Why are eno1 and eno2 in this order?

I've just installed a Fedora 21 Workstation system, and it's reversed the order of eno1 and eno2 from the CentOS 6 system that was on here before. lspci | grep Eth 00:19.0 Ethernet controller: Intel ...
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1answer
111 views

Allowing a device blocked by port-security

Lets say I have port security configured on a switch's ports like this: Secure Port MaxSecureAddr CurrentAddr SecurityViolation Security Action (Count) (Count) ...
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1answer
493 views

Can't find IPMI mac address

The MAC address listed under ipmitool lan print seems to be incorrect, since there is no entry in the arp cache for the set ip address, 10.224.242.121: # arp 10.224.242.121 10.224.242.121 ...
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86 views

MAC ID Binding to IP on Windows

Is there a way i can bind a certain IP to have traffic allowed if it has a certain MAC ID on windows routing and remote access or network policies? Basically Associated MAC ID to IP xxx.xxx.xxx.xxx ...
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124 views

Cisco 2801 - ACL example to prevent certain users in same subnet from accessing certain devices [closed]

May be a simple answer, but does anyone have an example of an ACL that would prevent certain users (preferably based on MAC address, so that I can not have to deal with static DHCP addressing) from ...
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1answer
34 views

Bridge behavior when MAC address is not found

Lets say, a uni-cast packet is sent from one system to another system. The packet passes goes to the bridge. But the bridge does not have any information about the MAC address of the destination. What ...
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1answer
436 views

Devices with MAC's manufacturer section “00:FF:01”?

While monitoring my office's network, I have seen a huge amount of traffic coming from devices whose MAC address manufacturer part (the three most significant octets) is 00:FF:01 I can't see the ...
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210 views

How can I get a report of all MAC addresses nearby? [duplicate]

I am trying to get an idea of how to get a list of all the MAC/IP's near my network. I've tried arp -a commands (What I found from some previous searching.) but those are not showing any of the ...
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58 views

Wireless Client missing from MAC table

I am currently having problems with Wireless Clients loosing network connectivity, though still displaying a connection to their Wireless Access Point. I have 4 Wireless APs, each a Cisco WAP321 ...
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2answers
116 views

Capture a packet at the MAC layer

I want to implement a security solution similar to MACsec that captures a packet in its entirety (including the MAC header) at an intermediate network node (e.g linux based switch), perform some ...
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82 views

Do some network administrators assign MAC addresses with an unassigned OUI?

I am in a situation where I have observed MAC addresses on a network that do not belong to any assigned OUI range, and this is causing some issues. I suspect the cause here is a heavy use of ...
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65 views

Network access sometimes lost, disabling port security temporary solves?

I have network based primarily on Edge-Core managed switched. Port security with max mac count = 1 is enabled, DHCP snoopping enabled. Some clients have troubles with accesing network, but when I ...
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2k views

Do cellular network adapters (3G/4G/LTE) have MAC addresses?

We are implementing SSH restrictions by restricting by MAC address in iptables. Without the MAC address restrictions, using an app like iSSH, it's easy to access my server on the go to check on it's ...
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1answer
149 views

Does the IP -> Ethernet multicast address mapping ambiguity matter for IGMP snooping switches?

There are 2^28 possible IP multicast addresses, but only 2^23 possible Ethernet (MAC) multicast addresses (http://technet.microsoft.com/en-us/library/cc957928.aspx), which is why e.g. 224.1.1.1 gets ...
0
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1answer
137 views

Linux static dhcp ip for visitor access internet without requesting MAC address? [closed]

Currently, my company internet access for visitor are required to request MAC address from them if they want to access to internet. Can we do something like the Hotel wifi? they just access to the ...
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1answer
282 views

Can RADIUS offer protection against spoofed MAC addresses accessing resources protected with MAC Authentication

When running RADIUS via WPA2 Enterprise and 802.1x, clients wishing to access the network must provide valid credentials. However, this does not stop malicious clients forging valid clients MAC ...
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229 views

Why does IPTraf show multiple MAC addresses for my interfaces?

Hopefully a simple question with a simple answer. I thought each NIC had a single MAC address. However, as can be seen from the IPTraf output below, I have multiple MAC addresses for both my eth0 and ...
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1answer
7k views

Two Identical mac addresses on the same lan - Tracking one down?

So I've been playing around with nmap, and found a curious problem, two devices in the same subnet have the same mac address. I would like to track down the second mac, as the first one is the sonic ...
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345 views

Finding NAS devices on the LAN

Thanks to some lax record keeping by our (ex! :-) network manager I'm tasked with finding what QNAP and Synology NAS devices exist in our company. We have several hundred offices scattered across the ...
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How can I set up a transparent proxy using squid and squidguard which has time-based acl based on MAC addresses?

I have a linux based server and I want to control access to internet based on MAC addresses of devices. How can I do that?
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ARP responds with single MAC address on Linux server with multiple interfaces on the same network

Linux server has 2 active network interfaces: IF:eth1 IP:192.168.1.1/24 MAC:11:11:11:11:11:11 (1GbE) IF:eth2 IP:192.168.1.2/24 MAC:22:22:22:22:22:22 (10GbE) The idea is that the ...