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 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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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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17 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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Monitor Internet Traffic Based on MAC Addresses [migrated]

I have a limited ADSL connection in my house. I want to monitor how much traffic each device connected to my router is using. I use a D-Link DSL-2730U as router. As far as I know there is no custom ...
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33 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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17 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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114 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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83 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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67 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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70 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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71 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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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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51 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
70 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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240 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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61 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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200 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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59 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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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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27 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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292 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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133 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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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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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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68 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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53 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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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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94 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 ...
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130 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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196 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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170 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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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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187 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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615 views

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 ...
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812 views

nmap and arp-scan inconsistent IP-MAC results

I seem to get variable and inconsistent results for the IP/MAC addresses from a particular machine, using nmap or arp-scan. The machine has 3 interfaces, and this is what it shows: $ uname -a Linux ...
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Strategy for forcing cam table updates from custom hardware

I have a system that consists of a control PC, two layers of switches, and 50 custom devices. The PC continuously streams a total of 5.8MB/sec (6000 ethernet frames/sec) to the devices. I have ...
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How to get a report of all mac addresses on another subnet?

We have an MPLS consisting of two branches: Location1 and Location2. I am using the Softperfect netscan to report all ip addresses and mac addresses of devices on Location1 where my workstation is ...
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876 views

Can I run a single DHCP Server for all branches of an MPLS?

We have a two-location MPLS. I am told by the ISP that I can have a single DHCP server to service both branches. But I don't understand this. Consider this: Location1 (Host branch with the DHCP ...
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Network Switch Terminology (MAC address table) [closed]

When a switch has the ability to learn what MAC addresses each of its ports serves, then uses that to determine which port to send ethernet packets out, what is that feature called? Also, does every ...
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120 views

Is recipient's MAC address necessary for TCP connections across the internet? [closed]

I want to estabilish TCP connection over the internet between 2 computers which are in different local networks (the local networks use wifi). I have looked for description of TCP protocol, ...
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1answer
816 views

Questions about bridging VLANs

If, across the same building, I have two physically separate networks to connect devices together via simple switches, my understanding is that I could save myself some hardware-complexity if I were ...
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1answer
4k views

How to use Calling-Station-Id on a per user basis in freeRADIUS?

I am trying to limit every user to a small set of Mac-IDs in RADIUS, by directly including the appropriate information in the users file. It would be acceptable even if every user was limited to one ...
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137 views

iptables arp compare and execute

EXAMPLE: iptables :internet - [0:0] -A internet -m mac --mac-source 48:5D:60:FC:29:B0 -j RETURN COMMIT [root@localhost:~ ] $ arp Address HWtype HWaddress Flags Mask ...
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Keepalived failover not working for Static NAT target behind Cisco ASA

I've got a Cisco ASA[0] with a pair of Linux boxes in the DMZ running Keepalived and HAproxy acting as a load-balancing failover pair for another pair of Windows servers, also in the DMZ. I'm ...
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Move IP from one server to another without disruption

I have an internal DNS server running on a VM. I've rebuilt the server from scratch in a new VM, and I want to cut over from the old to the new at some point. In order to do this, I'll need to take ...
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Second IP for VPS on VmWare ESXI?

I bought a VPS Server run on vmware ESXI and this server just had one IP; Now I decided to ask from the reseller to give me another IP; He says in order to do that he have to remove my account and ...
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1answer
2k views

Assign two static IP addresses to one mac address

Can Isc-dhcp-server give two static ip addresses to one mac address? I have several Genexis terminals in my network. Each terminal have two interfaces, one for public traffic and one for a management ...
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3answers
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How to prevent MAC spoofing?

I want to define in my Cisco switch a whitelist of allowed MAC, but MAC spoofing could allow any host to connect. How can I prevent MAC spoofing?