i appreciate the added info again. after reading your previous response, i went web searching and found interesting info about oui's (
https://en.wikipedia.org/wiki/Organizationally_unique_identifier) that seemed to be at least part of what you were referencing. i couldn't tell one mac address or oui lookup website from another so i didn't try any of them.
my thought is still that because of the uniquely identifying nature of a mac, i personally would prefer not to post mine and would continue to suggest the same for others. i did note that
inxi -Nnxxz provides at least the vendor and device id's.
part of my reasoning for being careful with a mac is (for example) from the macchanger package description (
apt show macchanger on debian- or ubuntu-based systems):
i promise i'm not trying to just be contrary, argumentative or overly paranoid. i just feel like the -z option for inxi filters mac addresses for a legitimate reason.
Media Access Control (MAC) addresses are 48 bits long. That's six "octets" (bytes), usually delimited with colons, but I have seen hyphens. The first three octets are assigned to the manufacturer when they request it. No other manufacturer will use it without permission.
TL;DR:
You can freely post the first three octets for any device and you will not lose privacy, other than sharing the manufacturer of a device you bought. The first three octets will be common for everyone who bought that same device. I would not be concerned about doing that.
MAC Addresses Do Not Normally Escape Your Local Network
In general, MAC addresses should not escape the confines of your home network. The MAC addresses are used by the local Ethernet or WiFi (or Bluetooth) network to move packets between computers and routers, but only on the "local link layer", aka "Layer 2" in your home network. Once your packets reach the internet, they will have the MAC address of your router and even that will be lost at the next hop. The IP datagram that was inside your packet moves along the internet towards its destination getting unwrapped and wrapped by each router as it moves towards its destination. (Try the command "traceroute linux.org" to see the route that your packet takes to get to Linux.org, but be aware that the traceroute command may not be installed or on the default PATH for every Linux distro by default.)
MAC Addresses Can Be Changed for Some Devices
In theory, MAC addresses are unique and permanent. In reality, some devices let you change a MAC address for yourself. I change the MAC address on my firewall/router when I want a new IP address from our internet service provider. I am here as a refugee from another forum. If I wanted to peek at that old forum (I don't), I would change the MAC address of my router, and use that to change my public IP address. The forum administrators would not know that I am the same logged-out person who belonged in the past.
Randomized MAC Addresses
Apple and others are randomizing MAC addresses to prevent tracking. Stores monitor your phone's WiFi MAC address as you walk around and used it to track your activity. If you go in another branch or cooperating store that uses the same technology, they will use your phone's MAC address to know that you are the same shopper visiting both stores. Think: Starbucks, etc.
The response to the tracking is randomized MAC addresses. (It drives me nuts, because when I review the logs, I can't tell my partner's iPad from her phone from our young adult's Mac and phone.) I get the value of it, but for me at home, the randomization is a pain and consumes licenses on my firewall router, which counts IP addresses in use. I get the privacy value, but it makes firewall incidents more challenging to figure out.
I learned about randomized MAC addresses and the issues around them after I noticed the change in our network's behavior. By coincidence, there is a detailed article about randomized MAC addresses in the very same journal where I created a thread a few days ago. See page 12 of the journal issue that I described in this thread:
https://www.linux.org/threads/an-unusual-history-of-the-internet-worth-sharing.45672/
MAC Addresses Can Leak
Because they are (in theory) unique to your device, its MAC address can be used to identify and track you and your activity, associated devices, etc. Because it uniquely identifies you and your hardware, MAC addresses may be used or transmitted by third-party products, etc.
SUMMARY:
It is okay to post the first three octets of a six-octet MAC address if you are concerned about privacy. Be aware that your MAC addresses may have leaked out anyway because they can be used for tracking and other less desirable purposes.
(Minor edit 1 hour later: Fixed typos, auto-correct errors, slight re-wording in two places for clarification.)
