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.

Filter by
Sorted by
Tagged with
0 votes
1 answer
31 views

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 ...
user avatar
-2 votes
1 answer
52 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 ...
user avatar
1 vote
0 answers
308 views

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 ...
user avatar
  • 457
0 votes
3 answers
58 views

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, ...
user avatar
0 votes
1 answer
64 views

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 ...
user avatar
0 votes
2 answers
327 views

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 ...
user avatar
-1 votes
1 answer
118 views

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 ...
user avatar
  • 3
0 votes
2 answers
295 views

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) ...
user avatar
  • 101
0 votes
1 answer
286 views

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 ...
user avatar
1 vote
1 answer
699 views

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 ...
user avatar
  • 121
0 votes
1 answer
210 views

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 ...
user avatar
1 vote
0 answers
45 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 ...
user avatar
  • 159
0 votes
3 answers
4k views

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 ...
user avatar
1 vote
2 answers
46 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 ...
user avatar
  • 11
0 votes
1 answer
126 views

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 ...
user avatar
  • 163
1 vote
1 answer
2k views

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 ...
user avatar
  • 113
0 votes
2 answers
3k views

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 ...
user avatar
0 votes
2 answers
79 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....
user avatar
0 votes
2 answers
781 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 ...
user avatar
0 votes
0 answers
68 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 ...
user avatar
  • 135
0 votes
1 answer
55 views

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 ...
user avatar
  • 101
2 votes
1 answer
575 views

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 ...
user avatar
0 votes
1 answer
870 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 ...
user avatar
  • 113
2 votes
1 answer
912 views

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 ...
user avatar
-4 votes
1 answer
121 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 ...
user avatar
  • 1
3 votes
1 answer
1k 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 ...
user avatar
  • 205
1 vote
1 answer
152 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 ...
user avatar
  • 409
0 votes
0 answers
4k views

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 ...
user avatar
  • 1,604
2 votes
0 answers
3k views

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. ...
user avatar
  • 121
0 votes
1 answer
1k 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 ...
user avatar
  • 101
0 votes
1 answer
1k views

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 ...
user avatar
  • 159
2 votes
1 answer
362 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 ...
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 ...
user avatar
-2 votes
2 answers
2k views

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?
user avatar
3 votes
1 answer
2k 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 ...
user avatar
0 votes
1 answer
2k 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 ...
user avatar
0 votes
1 answer
3k 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 ...
user avatar
  • 1
1 vote
1 answer
5k views

ISC DHCP assign pool/subnet to certain MAC addresses

Hej, desperate here! I'm running isc-dhcp-server 4.1 here (with webmin but that's another topic) and want to give some options (tftp-server and bootfile) to network-components that I can identify by ...
user avatar
1 vote
1 answer
8k views

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 ...
user avatar
  • 11
2 votes
1 answer
4k views

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 ...
user avatar
  • 506
0 votes
4 answers
2k views

Why does two different interfaces on the same machine result in two different MAC addresses?

My machine named debian has two different MAC Addresses. One for Wireless and one for LAN. I thought a device only had a single MAC address. How is this possible?
user avatar
1 vote
1 answer
2k views

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 ...
user avatar
  • 287
4 votes
1 answer
1k views

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 ...
user avatar
  • 233
1 vote
2 answers
3k views

How to find a server connected on network?

earlier this week we physically installed a machine in our server rack and connected it to our network switch. It has Scientific linux installed but we don't have a user account set up to log into. We ...
user avatar
1 vote
0 answers
135 views

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. ...
user avatar
  • 133
2 votes
1 answer
231 views

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 ...
user avatar
  • 133
0 votes
1 answer
794 views

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 ...
user avatar
  • 173
0 votes
1 answer
929 views

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....
user avatar
  • 1
0 votes
1 answer
2k views

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 ...
user avatar
  • 9
0 votes
1 answer
856 views

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 ...
user avatar
  • 101

1
2 3 4 5 6