Questions tagged [mac-address]
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 run several ESXi VMs that must have the same MAC address?
For various reasons I have to run a few (≈6) clones of the same virtual machine at my lab ESXi server at work and unfortunately the MAC address must not be changed between the clones. Changing IP is ...
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Get information about MAC address
My router (FritzBox 7330) shows tons of errors about a device that continuously try to connect to my network:
23.12.19 10:17:07 Registrazione del dispositivo wireless fallita: chiave wireless ...
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Changing MAC address on the Fly on old kernel 2.6.x
I'm doing some research on old kernels and running the following on 2.6.7 or 2.6.8 gives a resource busy error. But on 2.6.28 the command works as expected. How would I determine which kernel allowed ...
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Use IPv6 from MAC for DNS?
I am running a private cloud server and I am facing the problem that my DNS provider does not support dynamic update of the IPv6 address. I know that every IPv6 device has a 'default' IPv6 address ...
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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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Why do some unknown hosts show up with nmap option-sL , and not with -sn [and do I need to worry about them]?
Initial Disclosure
I am not a network engineer and my expertise in this area is low.
Background
while using nmap 7.70 with
nmap -sL
to look for the IP address of a known device on our local ...
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How to use my router's Mac Address on Pfsense installed on Esxi
My ISP bind my router's Mac address so only this router can connect to their pppoe server, now I want to connect it on Pfsense installed on Esxi for better configuration options but pppoe server is ...
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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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On VirtualBox, is there a way to set 'Reinitialize MAC address' as default?
When cloning a VirtualBox instance, is there a way to set the "Reinitialize the MAC address of all network cards" as the default?
Humans sometimes forget to tick this box, with the resulting horror ...
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IPv6 NAT information leakage [closed]
Edit: Since I was asked to edit this, I'll ask about an awfully specific issue. The question was obviously never about information leakage on OSI layer 7, since that wouldn't be a network issue.
I'm ...
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Different MAC addresses in packet and ARP table
What happens if a host on the network receives an IP packet with a MAC source address that differs from the MAC address in the local ARP table for that source IP?
The ARP table entry for that IP was ...
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Can I use source MAC of Ethernet packet for UDP reply instead of ARP lookup?
I'm working on an embedded platform with very limited resources where I need to build my own Ethernet frames.
If I need to answer a UDP request with a UDP reply, is it ever not OK to just send the ...
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Getting a static MAC address on AWS EC2
I want to ensure that my AWS EC2 instance has a static MAC address (for an app that ties the license to the MAC address). From what I read I just need to add an ENI to the instance to get a static ...
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How to solve Event IDs 16945 in the System logs Hyper-V MAC conflicts
After 3 years of running perfectly with Hyper-V I am all of a sudden having network problems with Hyper-V on win 2012 R2.
I set up my servers 3 years ago and never had these problem until this week.
...
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Get mac address based on ip in filter wireshark
i am a test engineer writing some test cases.
I am trying to write a test which has to be performed in wireshark.
However, my collegues aren't that "into wireshark" and i would like to keep it as ...
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ARP table not updated until response is sent
I'm executing the arp -a command on CentOS 7 in order to translate an IP address to a MAC address (since I can't access the source MAC of the layer 2 frame in Java).
I see a lot of cases where the ...
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Monitor for duplicate MAC addresses?
We just had our third incident of a duplicate MAC address from provided hardware in 2 years. I know it's possible to override the MAC in software, but detecting it during troubleshooting can take ...
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Possibility of detecting MAC address spoofing in a decentralized network? [closed]
The paper that has been published here: https://dl.acm.org/citation.cfm?id=3282283 proposes a consensus algorithm based on distributed voting process in which it claims that it would be possible to ...
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What happens if a USB Ethernet Adapter has the same MAC address as the PC's network card it is connected to?
What happens if a USB Ethernet Adapter has the same MAC address as the NIC?
Is it possible for internet connection to pass through the usb-ethernet adapter succesfully or not, in that scenario?
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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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Ubuntu 16.04, Keepalived VMAC
I'm trying to build up two redundant forward-facing load balancers (using either IPVS or NGINX), but first I'm trying to get the floating VRRP virtual-ip/mac to work properly before moving forward ...
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Physical interface MAC rather than macvlan MAC is sent as ARP response [closed]
On Arch Linux ARM (Raspberry Pi) Kernel 4.4.37, I created a macvlan e.g.
ip link add link eth0 mac0 type macvlan
The macvlan virtual NIC then appears in the list so I assign it an IP address, and ...
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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 ...
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Ethernet frames: what are the source and destination MAC addresses?
Imagine you have some network configured like this
+-----+ +------+ +------+ +-----+
|comp.|---|bridge|---|router|---|comp.|
| A |---| B |---| C |---| D |
+-----+ +------+ ^ +------+...
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How to reserve a static-ip on Mikrotik router for a device that is attached to a fixed router's Ethernet port
I am trying hard to figure out how can I force any DHCP client device connects to the port ETH10 on Mikrotik router get assigned a fixed IP-address.
Please note that the device MAC address is unknown ...
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ESXi VMs randomly lose network on reboot; only resolution to pull NICs and reassign new NIC driver with static MAC
We have one ESXi server (HP-ESXi-6.0.0 build-2492585) that has multiple VMs on it that have exhibited the following behavior:
When the VM is rebooted it will occasionally just lose all network ...
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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 ...
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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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Mac address not entering mac table of a huawei s5700 switch
We have a very strange problem, where certain ports refuse to learn the mac addresses of their hosts. For example host A is connected to switch S1 on port 0/0/30.
Each packet to host A results in a ...
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Port forwarding by MAC address problems
I have a server sitting behind a Huawei HG569 router. Port forwarding has been set up through the router and, when it works, it works as one would expect.
Now, the problem is that the HG569 router ...
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How can I change the MAC address of a network bridge in Windows?
I use DHCP reservation rather than static IP for convenience, and that relies on the MAC address of my computer.
I recently bridged my main adapter with my VirtualBox adapter. When things stopped ...
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How can I set the external interface for my bridge to be the same as my primary interface using networkd?
I've created a virtual bridge bridge0:
bridge0.netdev:
[NetDev]
Name=bridge0
Kind=bridge
bridge0.network:
[Match]
Name=bridge0
[Network]
DHCP=yes
and attached my primary interface eth0 to it
...
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How does VXLAN prevent duplicate MAC addresses?
It seems to me that VXLAN network identifier(VNI) works silimar to a prefix keeping identical MAC addresses on different VXLAN segments separate, so that they can coexist without duplication issues.
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VXLAN format details
Learning about VXLAN I found in a document:
...VTEP1 then adds a VXLAN header
that contains the VNI to the Ethernet frame, encapsulates the frame in
a Layer 3 UDP packet, and routes the packet ...
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Is it possible to isolate a network device from the rest of the LAN via its MAC address ?
Is it possible to isolate a network device from the rest of the LAN via its MAC address ?
Im familiar with creating a VLAN based on a tagged port of the network switch, but is it possible by ...
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KVM guest not reaching externally (OVH, failover IPs)
Both host and guest are running Fedora 26 server edition. Host is from OVH, guest is ISO from Fedora directly.
I've trimmed anything regarding TXRX and loopbacks for the sake of brevity.
Main IP a.a....
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Linux easy way to extract MAC address per device
I am dealing with post systemd crapstorm where devices get renamed to eno1,2,3 or sometimes rename1,2,3. I don't run systemd as init system but unfortunately udevd is that systemd infected garbage ...
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Windows Server 2012 DHCP Failover and MAC address replication
I'm stuck with a problem in my configuration.
We have a domain controller who works also as DNS and DHCP server. Yesterday i deployed a secondary DHCP server and configured it in a failover cluster ...
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how to answer a who has arp request
Ok this is a stupid question i know, but bear with me.
I started a new job and the networking is terrible, there are a bunch of dumb switches on top of dumb switches.
We are running a 10. network ...
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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 ...
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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....
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Resolve MAC address to vendor BASH
As the title states, I was wondering if I could resolve a MAC address to a vendor on Linux, with BASH.
I would rather not use NMap, as I want it to be quick.
Example: e0:b9:e5:9e:59:00 -> ...
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Why are there different types of bond configuration policies in linux, instead of one that can give a combined throughput and fail-over configuration?
I am confused and not able to understand exactly the actual concept behind it. At switch level, what happens that prevents to use one globally accepted bond configuration policy?
And I don't ...
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How can I create a top priority firewall rule for a trusted mac address?
I want to accept all packets sent to my centos7 VPS from my device regardless of options defined on public zone. (I want to remove ssh service from public zone and just be able to connect from my mac ...
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Using Ipset and Iptables for MAC address filtering
I use MAC address filtering on my Linux router. Here is what I have done:
iptables -A INPUT -i eth5 -m mac --mac-source 00:07:e9:84:2b:99 -j RETURN #User: Someuser
iptables -A INPUT -i eth5 -j DROP
...
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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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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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Is a Network Switch IP-Aware?
I have some very trivial basic questions about networking, but I find varying information on that, so I just wanted to settle this.
As far as I understand a Network Switch handles traffic "...
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No network after MAC address change
I'm running a CentOS 5.4 box for which I need to spoof a MAC address in order to make a certain software work (nothing illegal going on, before you ask).
Problem: Whenever I try to change the MAC, I ...
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Why do some mac-addresses repeat so often?
My application queries mac-addresses of client computers where it runs and stores them on the server. When I analysed the server DB, I found that some mac-addresses repeat 100-150 times. I.e. ...
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