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 generate a random MAC address from the Linux command line

How do I generate a random MAC address from the Linux command line? I search for a solution that only requires standard tools commonly found on the Linux command line. The MAC address will be used ...
0
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1answer
40 views

Can't ping gateway after upgrading to Ubuntu 16.04 | arp issue?

After upgrading to Ubuntu 16.04 from 14.04 I can't ping gateway, at first interface eth0 wasn't starting up, and I read that refreshing new mac address would fix that, so I decided to remove the ...
0
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0answers
17 views

Fortigate software switch, lost packets with connected switch

I have a Fortigate 60D device, with software switch configured ("lan" - vlan 1), plus other vlan interfaces (2, 3) on top of the hardware switch. I have a Dell managed switch connected to the FG-60D, ...
0
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1answer
17 views

Spacewalk/Cobbler system with multiple interfaces/MAC

I have bare metal provisioning set up with a DHCP/PXE server and a Spacewalk server. I'm using cobbler system records to match a machines MAC address to the system profile. Basically: cobbler ...
0
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0answers
10 views

Are MAC addresses simple unique identifiers, or are there rules for categorizing MAC addresses?

Background Context: I've been scratching my head over an issue with my router picking up multiple VMs as a single device. I'm able to reserve ips for the separate MAC addresses, and as far as I'm ...
0
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1answer
20 views

How to view dnsmasq client MAC addresses dynamically?

If I have already known the client IP, I know there's /var/log/dnsmasq.log and it contains logs such as Jun 13 12:22:42 dnsmasq-dhcp[499]: DHCPACK(wlan0) 172.24.1.110 34:12:98:11:80:bd ones-iPad ...
0
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1answer
22 views

How to get the correct MAC address of Windows Server 2008 out of multiple MAC addresses?

I want to know the unique MAC address of my Windows Server 2008 R2. When I used getmac command in command prompt I got a list of MAC addresses(6 count) under Primary Address header. Could you please ...
0
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0answers
48 views

Dnsmasq - assign different subnets based on MAC address “family”

I have an experimental network with about 60 client machines. The client MAC addresses are all divided into 3 "families" with different address beginnings. The server is an Ubuntu machine running ...
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3answers
58 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
90 views

get mac address and replace from a file [closed]

I have two interfaces ethernet: Example: ifconfig | grep direcciónHW enp2s0 Link encap:Ethernet direcciónHW b8:2a:72:01:01:02 eno1 Link encap:Ethernet direcciónHW 9c:d2:1e:01:03:04 I ...
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0answers
20 views

“match hardware” in dhcpd.conf not working

I've been trying to get mac addresses with a certain OUI into a certain address pool. I haven't been able to get it to work at all. Here is a snippet of my dhcpd.conf and how it's applied. class "...
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2answers
65 views

Guest VMs cant reach each other on Different ESXi Servers

I have two vSphere EXSI 6 servers both setup with the same vSwitchs and connected to the same physical switches Server 1: eth0 => vlan143 (mapped to CORE/Management vSwitch) eht1 => vlan140 (...
2
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5answers
3k views

Find the network card mac address in Windows

How can I find the network card mac address in Windows (7)?
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0answers
32 views

Netgear Prosafe SRX5308 config with Virgin Superhub

We have just bought a Netgear Prosafe SRX5308 to provide load balancing with our 4 internet connections, but I am struggling to get it configured with our Virgin Media connection. The auto-detect ...
0
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1answer
70 views

iwconfig and arp commands report slightly different MAC addresses

I'm at a wifi hotspot where, when I look up the router's MAC address by two different methods, I get slightly different results: $ arp -a ? (10.128.128.128) at 00:18:0a:58:WX:YZ [ether] on wlan0 ? (...
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0answers
44 views

When a computer wants to send a IP packet to another computer in the same network, how does it know the destinamion MAC address of that host? [closed]

So I know that switches are better than hubs because they can forward an Ethernet frame exactly to the host that has that specific destination MAC address. However, when two computers communicate, ...
0
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1answer
29 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 ...
5
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1answer
195 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 ...
7
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4answers
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Can I use nmap to discover IPs and mac addresses?

When I need to locate the IPs of devices by their mac address on a Windows system, I normally use Advanced IP Scanner (from radmin.com) to scan the network, then I use arp -a to list the mac addresses....
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1answer
86 views

Does a private MAC Address range exist?

I need a set of MAC/Ethernet addresses that I do not have to worry about collisions with, analogous to 192.168.x.x: addresses that will NEVER be assigned to real hardware.
3
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1answer
1k 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 ...
3
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0answers
72 views

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 ...
1
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1answer
144 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 ...
0
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0answers
54 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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2answers
74 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 ...
0
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1answer
69 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 ...
4
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4answers
26k views

What happens if two computers have the same MAC?

Possible Duplicate: Can duplicate MAC addresses on same LAN cause trouble? What happens to network traffic on a switched LAN if two devices have the same MAC (probably because one is cloning ...
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0answers
30 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 ...
0
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1answer
88 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 ...
0
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0answers
25 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 ...
2
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1answer
60 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 ...
48
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6answers
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What range of MAC addresses can I safely use for my virtual machines?

I want to assign my virtual machines MAC addresses so that I can configure DHCP reservations for them so that they always get the same IP address regardless of which host hypervisor they are running ...
0
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1answer
83 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
175 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 ...
1
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1answer
309 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 ...
0
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0answers
39 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 ...
170
votes
13answers
31k views

Why couldn't MAC addresses be used instead of IPv4|6 for networking? [closed]

I am reading up on TCP/IP and other related protocols and technologies. MAC addresses are described as being (reasonably :) unique, and as having a large possibility space (several hundred trillions), ...
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0answers
78 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 ...
3
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0answers
280 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 ...
0
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2answers
21k 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 ...
3
votes
1answer
540 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 ...
5
votes
5answers
7k 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 ...
0
votes
2answers
208 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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0answers
50 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 ...
0
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1answer
103 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 ...
3
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0answers
151 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 ...
2
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1answer
164 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 ...
0
votes
1answer
105 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 255.255....
0
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1answer
829 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 (10.224.242....
0
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1answer
1k 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 ...