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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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 ...
0
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1answer
43 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 ...
0
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0answers
29 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 ...
1
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2answers
27 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 ...
0
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0answers
45 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 ...
0
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0answers
29 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 ...
-3
votes
1answer
114 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 ...
0
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1answer
58 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
78 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 ...
0
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0answers
32 views

STP/RSTP: what switch should do with MAC table on a port after changing STP role of this port?

I have two switches and two active links between them. Spanning Tree Protocol is enabled on both devices, and port roles are assigned correctly: there are two Designated/Forwarding ports on RootSwitch ...
0
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1answer
87 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 ...
0
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1answer
95 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 ...
0
votes
1answer
3k 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 ...
0
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3answers
116 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 ...
-1
votes
1answer
394 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?
2
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2answers
658 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
votes
1answer
442 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 ...
1
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1answer
59 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 ...
2
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2answers
127 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 ...
2
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3answers
322 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
69 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 ...
-1
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2answers
73 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, ...
2
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1answer
270 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
votes
1answer
2k 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 ...
1
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1answer
101 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 ...
2
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0answers
193 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 ...
1
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1answer
75 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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votes
1answer
200 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 ...
1
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1answer
1k 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
749 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?
1
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1answer
75 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 ...
0
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0answers
69 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
93 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 ...
0
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3answers
79 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 ...
0
votes
2answers
60 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 ...
0
votes
1answer
407 views

Two NIC card with same mac address

Yes its very strange but I have got two server having same H/W MAC address. The issue which I am facing is again very strange. 1st Server is normal windows server. 2nd Server is running KVM on ...
0
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2answers
2k views

Multiple NICs with IPs from same network at Linux host respond to a single MAC

CentOS host is armed with multiple NICs. All NICs are bound to the same subnetwork (let it be 10.0.0.0/24). Their IP configuration is provided with DHCP server (as reservations). While trying to get ...
0
votes
1answer
152 views

IP address from a MAC address

I'm writing a class to integrate a POS card reader device to our software. In order for it to work I must know what IP it's using. We were given some sample code by the service provider and the way ...
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votes
2answers
72 views

Mac Address automatically changed [closed]

In a network many servers and workstations and cameras DVR are working together but any instant the MAC address of one server (ip-192.168.12.1) and DVR (ip 192.168.12.176) which have different MAC ...
10
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7answers
778 views

What's a good way to handle multiple devices with the same MAC address on one network?

The devices I'm working with come off the production line all set to the same MAC address. I can set each one to have their own static IP, and I'm wondering if there would be a way to connect them to ...
3
votes
1answer
162 views

Gather mac addresses of domain computers, preferably from command line

In preparing to move to a domain and SCCM to manage machines in a new office I need to gather their MAC addresses. I could go from machine to machine, run ipconfig and gather the ip, but that would ...
2
votes
1answer
896 views

Why are eth0 and vmbr0 (bridge) having the same MAC addresses?

I configured my Debian (with KVM on board) as following: /etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 inet manual auto vmbr0 iface vmbr0 inet static address ...
2
votes
2answers
358 views

Any standard protocol to find all systems' MAC addresses and possible hostname connected to a switch

I have servers and storage arrays in a composite lab and intermediate switches. I want to get a list of all the MAC addresses of the systems connected to each switch. It should be switch vendor ...
2
votes
2answers
3k views

iptables, allow access from certain MAC addresses

Presently, I limit which clients can access my server by using IP addresses via iptables, only approved IP addresses can connect. However, the problem with this is if a client is on a laptop and goes ...
0
votes
3answers
2k views

Linux: find MAC Address for unconfigured card

I have a linux system for which I want to create my own udev rules for the nic. Currently there are no rules, so no ethX is configured. I can't do ifconfig (it is not showing any interfaces besides ...
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1answer
50 views

Server 2003 Filter mobile devices via MAC

At one of my client's sites I need to keep my users unauthorized devices off the wireless. They all know the SSID and Password because many of them have laptops that need the wireless. I'm running ...
0
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1answer
487 views

Juniper networks mac addresses of switches in a LAN

I have a LAN consisting of switches connected to each other then to some devices, How to get the mac address of the switch connected to a specific port on the main switch then get the ports and device ...
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2answers
1k views

Show mac-address table on custom interface in FreeBSD and Linux [closed]

On switches I can show mac addresses on any port by "show mac-address-table port X" Is there any way to do this on FreeBSD and Linux systems?
2
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1answer
2k views

Hyper-V MAC Address collisions

I am trying to troubleshoot a performance issue with our application on a customer network. We do not support the network infrastructure, and the people that do have effectively washed their hands of ...
3
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1answer
403 views

Windows Server 2008 ARP Cache Poisioning

Recently ran into a very strange problem. Several applications were having issues communication through our F5 Load-Balancer. When we looked into it we found that the router had an incorrect ARP and ...