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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Tracking the network traffic from an unknown MAC address on WIFI [closed]

I have a MAC address on my WiFi network that I do not recognize. The unknown device asks for, and receives, an IP from my dhcp server. I tried the following to find out the origin: All my devices (...
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Softether VPN Client - vpncmd - Two different MAC addresses for one virtual interface

I've encountered strange MAC behaviour in my system - I've got 15 Linux Ubuntu machines with NetworkManager disabled and dhcpcd as DHCP client. Those devices connect to my SoftEther virtual HUB and as ...
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How to find HA interface mac address in Fortigate?

We have two Fortinet and HA them. In "primary" I can see the Mac address for all interfaces easily in Network -> Interfaces -> Edit Interface. but I can't find the Mac address for &...
s.mostafa.b's user avatar
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Blocking all trafic except legitimate router

In the business centre where I work, all clients are on the same network. The Internet <--> building router <--> building network (including rogue DHCP, etc) <--> my router's WAN ...
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network does not work for VM after a while, only resolves after changing MAC

I have installed pfSense as a KVM guest in a Debian 11 host using libvirt. The host has two interfaces. One is attached to the VM using macVLAN driver, and serves as pfSense's WAN interface. The other ...
Mustafa Mohiuodin's user avatar
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netplan mac address matching doesn't seem to work

I have a small pc box that only have one network interface, and since I needed 2 more interfaces, I've bought two usb network cards. Both same manufacturer. I wanted to rename interfaces (since they ...
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Debian: Where does a bridge interface store its MAC address and how can I change it?

I have reinstalled a computer and since I need several similar computers, I duplicated the hard disk with dd. On the target systems I have adjusted /etc/hosts, /etc/hostname and /etc/network/...
th0masrad's user avatar
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Filtering traffic by MAC - nftables

TL:DR : I am building a network tap with a raspberry-pi that must remains stealth. I have a bridge (br0) between the switch interface (eth0) and the workstation (eth1). Here is how i am building it (...
m4ki3lf0's user avatar
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2 answers
826 views

Network is gone when I start arp spoofing [closed]

So for context I have two virtual machines one is running on kali linux which is the "Hacker's" machine and the other one is running on windows 10 pro which is supposed to be the victim's ...
LuckyCoder3607's user avatar
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Router forces to use netcard's hardware mac

I'm trying to connect to a network that manages device connections by it's mac. So, I want to connect a device, which has no interface to connect it properly by itself I decided to use a different ...
Undermouse's user avatar
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Can pre-assigned IP addresses be preserved when using wi-fi extenders?

I'm considering using a wi-fi extender. It will work fine for lap-tops, tablets, etc. that need a connection but don't need a fixed DNS entry with preassigned IP addresses. But wi-fi extenders modify ...
Ray Butterworth's user avatar
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TAP interface generating same MAC address on multiple servers

We use PeeerVPN on Debian 11 servers and we recognized that the TAP interfaces on multiple servers comes up with the same MAC address (it should be random generated). Is anyone experienced the same ...
Arany Péter's user avatar
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Decode UID from dhcpd.leases

I have am testing a device on my network which has this lease assigned: lease 192.168.110.85 { starts 3 2022/07/20 16:12:37; ends 3 2022/07/20 16:22:37; cltt 3 2022/07/20 16:12:37; binding ...
Johannes Linkels's user avatar
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dnsmasq: Change DHCP range based on group of MAC address

Is it possible to change the DHCP range dnsmasq gives out based on the MAC address block. For example, I want all MACs in the block 00:0C:29 to have a different DHCP range compared to every device on ...
foxtdev's user avatar
-2 votes
1 answer
265 views

Discover IP address of the device knowing only MAC address

While "wiresharking" the network, You may come across packets that looks like THIS eth.src to eth.dst (mainly colored white).. sometimes Wireshark recognize protocol LLC, NDP etc.. but ...
apech zzz's user avatar
2 votes
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Filtering traffic by MAC address with nftables

TL;DR: when spoofing MAC addresses, how can I make sure the real addresses won't be leaked to the rest of the network using nftables ? Context For network security training purposes I am currently ...
Kate's user avatar
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Network layer communication with multiple hosts with the same IP but different MAC addresses

Due to an unfortunate (mis-)configuration issue I am having ~100 hosts of which the IPv6/IPv4 (even the IPv6 link-local) addresses are all the same and which for the moment I cannot change. However, ...
Simon Fromme's user avatar
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How to send/broadcast ipv6-mac maping cache update request for IPv6 IP

We can update IPv4 neighbors by using arping command. I have used arping -A -I -c <interface_name> <IP_address_of_interface> with success. what is the command to update mapping of IPv6 ...
tushars's user avatar
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2 answers
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Static ARP Entries aren't being added

So I'm trying to create a static ARP Entry with the ip and MAC Address of my router. I'm currently using admin command prompt and the command arp -s [ip] [mac address], but it isn't working. Every ...
Ryan Ding's user avatar
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1 answer
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Do computers have IP address? [closed]

Everywhere I search some people say 'a computer has a permanent IP address' and some people say 'it doesn't but has only when it is connected to the internet through a router'. So my understanding is ...
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can ping but not arping via OpenVPN

I'm working on a remote machine using OpenVPN at a customer's network. The IP addresses there change dynamically and (until they get hostnames to work properly which is not in my hands at this point) ...
Cookie's user avatar
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Mac address flapping during VM migration in WSFC

I am trying to troubleshoot an issue with our servers on a customer network. We do not support the network infrastructure. For example, I have 2 nodes(WS2019) in the Failover Cluster. Each NODE have 2 ...
Andro Leo's user avatar
1 vote
1 answer
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What are the symptoms of an IP address conflict?

System administrators must take special precautions when setting up two DHCP servers on the same network. The most common problem caused by competing DHCP servers is an IP address conflict. Windows is ...
Rick's user avatar
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How to give permissions to local computers using computers' MAC addresses in Windows Server 2016 for file sharing

I have the following issue: I have a server with Windows Server 2016, and I need to use it only for saving, reading, and modifying files with file sharing. The way I have the restrictions is with ...
Jorge Ortiz's user avatar
1 vote
0 answers
102 views

Same VIP different MAC

I am observing this behavior on a dual-homed server that is sending traffic in active/active mode on its 2 links connected to the same uplink switch. The server is running IPMP so it generates traffic ...
gaetano's user avatar
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3 answers
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Centos 7.6 MAC addresses change for a network interfaces

On one of the CentOS Linux release 7.6.1810 (Core) server the mac address's of networfaces got changed e.g. eth0 has eth3's mac address and so on . Does anyone know why this happens and how to resolve ...
Babasaheb's user avatar
1 vote
2 answers
90 views

LAN static lease for Hyper-V VMs

I have a question about reserving IP addresses for VMs that run on my laptop. In this case, my laptop serves as a switch. But the thing is, how can I lease a VM an IP address in my LAN by MAC, as all ...
Abraham's user avatar
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1 answer
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if all of the world used IPV6, there is no need to have mac address anymore?

Mac address can not replace IP address, because Mac address is immutable, and there is no Prefix concept in Mac address. So why IpV6 can not replace Mac address? Do we still need Mac address when all ...
Jack's user avatar
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1 answer
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Is it possible to check the MAC address of TCP-connected host (on same LAN)?

I have an Ethernet LAN (192.168.1.0/24) with a number of hosts, which are all assigned addresses over DHCP by a router. Due to the way that DHCP is set up the IP addresses of particular devices can ...
Svet's user avatar
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Azure Network Interface physical MAC address

I am trying to run some third-party software on an Azure Linux VM but their licensing is tied to the MAC address. The private and public IPv4 IP addresses of the Network Interface for the VM are both ...
kilgoretrout's user avatar
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2 answers
152 views

Why is the mac address that appears on my computer the same?

I use the 2 ethernet interface on the my system board, eth0 / eth1(usb to ethernet) like the followings. root@E3-RDP:~# ifconfig eth0 Link encap:Ethernet HWaddr ae:a1:99:48:86:79 inet addr:10.10.0....
andykim's user avatar
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2 answers
1k views

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 ...
LapplandsCohan's user avatar
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73 views

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 ...
Mark's user avatar
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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 ...
E. Sommer's user avatar
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2 votes
1 answer
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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 ...
Mister October's user avatar
0 votes
1 answer
1k views

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 ...
Uzair Ali's user avatar
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2 votes
1 answer
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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 ...
fitcfitcfatc's user avatar
-4 votes
1 answer
130 views

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 ...
f384's user avatar
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4 votes
2 answers
3k views

Why is networkd changing the MAC addresses of my bonded interfaces?

When I add the config files below into /etc/systemd/network and restart systemd-networkd, I find that the MAC addresses of bond0, eth0 and eth2 have all been changed to a single, locally administered ...
Isvara's user avatar
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1 vote
1 answer
229 views

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 ...
Markus A.'s user avatar
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0 answers
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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 ...
TSG's user avatar
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2 votes
0 answers
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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. ...
Austin's user avatar
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0 votes
1 answer
2k views

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 ...
tomvda's user avatar
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1 answer
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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 ...
manash's user avatar
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2 votes
1 answer
643 views

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 ...
tudor -Reinstate Monica-'s user avatar
1 vote
1 answer
2k views

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 ...
Questioner's user avatar
-2 votes
2 answers
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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?
Heaven88's user avatar
3 votes
1 answer
3k views

hostapd: mapping MAC address to VLAN ID (static mapping via accept_mac_file)

I want hostapd to assign each station a given VLAN based on MAC address. BTW, my network is quite small. Using RADIUS would be an overkill. According to the hostapd manual: Optionally, the local ...
Pedro Abrantes's user avatar
0 votes
1 answer
3k views

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 ...
boardrider's user avatar
0 votes
1 answer
4k views

How to setup my MAC address to be static using OpenVPN on Ubuntu 16.04?

I'm connecting to a server using vpn connection. So, every time that I connect using this VPN, my PC (Ubuntu 16.04) always create a virtual netboard and gives to me a new MAC address. But for what I ...
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