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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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
83 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
76 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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33 views

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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56 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
66 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
64 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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1answer
41 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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46 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
62 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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200 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
51 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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152 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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1answer
55 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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2answers
89 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
26 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
274 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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1answer
129 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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46 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
80 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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63 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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2answers
779 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
90 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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1answer
126 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
184 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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158 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
5k 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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3answers
174 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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1answer
593 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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2answers
967 views

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 ...
3
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1answer
779 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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1answer
90 views

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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2answers
213 views

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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3answers
808 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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2answers
74 views

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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2answers
112 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
731 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 ...
2
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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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1answer
136 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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0answers
302 views

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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1answer
89 views

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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1answer
254 views

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 ...
2
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3answers
2k views

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?
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1answer
99 views

Host not showing in ARP even after broadcast

serverfault community. What I would like: to determine the current IP of a host (a networked camera to be specific) What I have: its MAC, its previously documented hostname and IP What I have ...
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86 views

How to detect on Linux that given MAC (HWaddr) is a virtual MAC and will change after rebooting?

Is it possible on Linux to detect automatically that given MAC (HWaddr in ifconfig output) is a virtual MAC and will change after rebooting. or alternatively is there a way to detect virtual network ...
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1answer
129 views

virtualization and MAC addresses

I'm having trouble with some VMware VM problems. Short story, how can I deploy a Windows server 2008 R2 server image to a lab environment with snapshots without MAC issues. Long story, I have a 2008 ...
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3answers
99 views

Assign MAC 64 in Debian

In /etc/network/interface I want to assign a 64-bit MAC address, but when I do, the MAC address just is a 48-bit random address. I'm using a Cubieboard with Debian 7.0, EMAC is on the hardware, so the ...
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2answers
72 views

Bridge (?) that is doubly-connected to a network [duplicate]

Note: I think my question has a poor title but I am not sure how to fix it, so please correct if you think of something better. In my office our phones are equipped with a "daisy-chain" port so that ...