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Pi4 mac not correctly registered by RPF?

Posted: Sat Nov 02, 2019 11:16 am
by HermannSW
When running host_discovery script on Ubuntu
https://www.raspberrypi.org/forums/view ... 4#p1560454

the "sudo nmap -sn $inet/$bits" command executed reports companies for mac addresses in my network.

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MAC Address: 40:B4:CD:B9:XX:XX (Amazon Technologies)
But the Pi4 reports "(unknown)", is the mac not correctly registered by RPF?

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...
Nmap scan report for raspberrypi4B.fritz.box (192.168.178.178)
Host is up (0.054s latency).
MAC Address: DC:A6:32:18:F9:F6 (Unknown)
...

Re: Pi4 mac not correctly registered by RPF?

Posted: Sat Nov 02, 2019 11:33 am
by HermannSW
My son asked me to do mac online lookup, and I did.
Two online services correctly reported that the mac address is registered.
So is the "(unknown)" the result of bad nmap on Ubuntu 18, or does the Pi4 report "(unknown)" for some reason?
https://dnschecker.org/mac-lookup.php

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DCA63218F9F6
Address Prefix 		DC:A6:32
Vendor / Company 	Raspberry Pi Trading Ltd
Start Address 		DCA632000000
End Address 		DCA632FFFFFF
Company Address 	Maurice Wilkes Building, Cowley Road Cambridge CB4 0DS GB

Re: Pi4 mac not correctly registered by RPF?

Posted: Sat Nov 02, 2019 11:45 am
by trejan
nmap has its own database of MAC prefixes that is stored locally. The copy packaged with your nmap is old. The latest version is here and does list Raspberry Pi Trading for DC:A6:32.

Re: Pi4 mac not correctly registered by RPF?

Posted: Sat Nov 02, 2019 1:46 pm
by HermannSW
Thank you, I see 2 Raspberry entries there:

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DCA632 Raspberry Pi Trading
B827EB Raspberry Pi Foundation
I just did "sudo apt-get update; sudo apt-get upgrade" on my "Ubuntu 18.04.3 LTS", but no additions, so I am up to date.
Not sure how long it will take on Ubuntu LTS to get the new version of nmap containing the Pi4 entry.

I just powered up my Pi 3B+ and that shows up correctly from Ubuntu:

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Nmap scan report for raspberrypi3Bplus.fritz.box (192.168.178.81)
Host is up (-0.084s latency).
MAC Address: B8:27:EB:51:FF:95 (Raspberry Pi Foundation)

This is not to be a Ubuntu only problem, even latest Buster on my Pi 3B+ does not know about the 4B ...

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[email protected]:~ $ sudo nmap -sn 192.168.178.178
Starting Nmap 7.70 ( https://nmap.org ) at 2019-11-02 14:45 CET
Nmap scan report for raspberrypi4B.fritz.box (192.168.178.178)
Host is up (0.11s latency).
MAC Address: DC:A6:32:18:F9:F6 (Unknown)
Nmap done: 1 IP address (1 host up) scanned in 0.40 seconds
[email protected]:~ $ 

Re: Pi4 mac not correctly registered by RPF?

Posted: Sat Nov 02, 2019 2:08 pm
by trejan
It is unlikely to be updated for Buster or your old Ubuntu LTS 18.04 install. Both of them have frozen the Nmap version with 7.70 supplied with Buster and 7.60 supplied with Ubuntu LTS 18.04. The latest 7.80 which will have the extra Raspberry Pi MAC prefix came out in August and is packaged as part of Bullseye and Ubuntu 19.10.