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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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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0answers
20 views

How can a PC have two logical addresses? [closed]

Is it possible for a single computer two have more than one logical address? If so, how? Please guide me. Thanks in advance. Thanks in advance.
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3answers
46 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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3answers
1k views

Look up manufacturer based on Mac Address?

I want to incorporate into a piece of software the ability to look up a manufacturer based on a mac address. By googling "mac address lookup" and similar, I have noticed several websites that make ...
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1answer
37 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
63 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 ...
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1answer
34 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
38 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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1answer
52 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
78 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
59 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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1answer
1k views

Ping server NETBIOS name returns wrong IP and “Destination host unreachable”

Problem server is Windows 2008 R2 VM running on VMWare ESXi 4 host. Single network adapter manually assigned single IP address (192.168.1.11). When I ping the server from any other network computer, ...
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2answers
52 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
56 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
523 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
61 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
77 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
60 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
81 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 ...
0
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2answers
271 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
228 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
46 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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1answer
75 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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0answers
50 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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3answers
58 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
55 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 ...
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1answer
173 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 ...
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2answers
364 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 ...
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1answer
107 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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2answers
50 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 ...
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7answers
584 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
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1answer
58 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 ...
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1answer
311 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 ...
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2answers
200 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 ...
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1answer
261 views

Broadcom NetXtreme II GigE Teaming Does Not Use Unique MAC, Causing Collisions

I currently have a new Dell server on my local (inside) network that I have setup to use three of the four nics to create a team. Examples below. NIC_1 - mac: 000000000001 - ip: n/a NIC_2 - mac: ...
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3answers
320 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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2answers
919 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 ...
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1answer
38 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 ...
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802.11 Wi-Fi SSID broadcast [closed]

Assume I'm a router manufacturer. I'm wondering if I can gather data about users that are seeking for available Wi-Fi networks. Maybe RTC/CTS http://en.wikipedia.org/wiki/IEEE_802.11_RTS/CTS ? I ...
0
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1answer
165 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
450 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
898 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
229 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 ...
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1answer
61 views

Possible MAC conflict in ESX

I have two virtual machines that are 10.1.1.10 and 10.1.1.20 in an ESX. I try to access theses machines by another network 192.168.1.0/24. The problem is that when I can ping one machine, I can not ...
1
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1answer
162 views

Redirect traffic on port 80 into apache for unknown macs, and into squid for some macs

I have a linux box behaving like a router that handles two network interfaces: eth0 for internet and eth1 for LAN. I set up iptables in order to redirect all the web traffic coming by the LAN into a ...
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0answers
24 views

How do clients “recognize” network servers for automount purposes?

Say I have two media servers on a single subnet. They have the same name, hardware, setup.. etc. Except for any UUIDs/MACs, they are the identical. How does my client tell them apart, especially ...
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54 views

Cisco 860 router series enabled MAC address filtering & set client count

Using a cisco 860 router, presuming a wireless network has been setup and activated. What commands can be entered to A) enable MAC address filtering, and B) Set the maximum client count
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MAC Addresses (in devices) [closed]

In what type of hardware are MAC addresses used besides routers? For example, could a MAC address be in printer or in a mobile phone? Yes, I am talking about Ethernet MAC addresses. Can you please ...
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4answers
2k views

How do I MAC filter with DHCP server

I want to Only allow certain MAC addresses to get a IP from my DHCP server, currently I use dnsmasq and I rather not change dhcp server but I'm open to other software aswell. However, I need to be ...
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2answers
5k views

Query a Windows DHCP server : find MAC from hostname

From my computer, I want to query my DHCP server to find a specific mac adress. I want to enter the hostname to search, and getting back the Mac address. Something like : netsh dhcp server scope ...