Freebox Server (Pop V8/ Delta V7 / Revolution V6 / Server Mini 4K)

  • État Close
  • Type de tâche Anomalie
  • Catégorie Non trié
  • Assignée à Personne
  • Système d'exploitation Tous
  • Sévérité Basse
  • Priorité Normale
  • Basée sur la version 4.4.1
  • Due pour la version Non décidé
  • Date d'échéance Non décidé
  • Votes 0
  • Privée Non
Concerne le projet: Freebox Server (Pop V8/ Delta V7 / Revolution V6 / Server Mini 4K)
Ouverte par Buggy (bugbuster) - 04/09/2021
Dernière édition par Marios Makassikis (mmakassikis) - 21/09/2021

FS#35529 - Bittorrent: Invalid IPv6 addresses announced via PEX

Excusez-moi if I’ve put it in the wrong category, I didn’t find anything better.

I have found two different ‘Freebox BitTorrent 2.0’ clients in the wild sharing invalid IPv6 addresses via Peer Exchange (PEX). To find out that it was the Freebox peer exchanging wrong IPs, I’ve blocked all other clients and waited for PEX process to repeat.

For example, my own IPv6 is: 2001:0db8:abcd:ef01::1
Then the Freebox BT 2.0 peer will start sending INVALID IPv6 addresses where the FIRST HEXTET is completely random. The rest stays correct. Here’s a real selection:

  • cc58:0db8:abcd:ef01::1
  • db1a:0db8:abcd:ef01::1
  • c47a:0db8:abcd:ef01::1
  • df36:0db8:abcd:ef01::1
  • c262:0db8:abcd:ef01::1
  • e885:0db8:abcd:ef01::1

All of the above are invalid as they weren’t yet allocated! See: and

The client presents itself as Client: Freebox BitTorrent 2.0, Peer ID: -FX0200-<omitted>
I do not know the exact OS/software version. But this is no longer a single occurence (not a hardware bug/bad RAM).

Merci beaucoup for reading.

Close par  Marios Makassikis (mmakassikis)
mardi 21 septembre, 2021 09:20:55
Raison de clôture :  Résolu
Commentaires supplémentaires de clôture :  firmware 4.5.0

Cette tache ne dépend pas d'autre tache

Buggy (bugbuster)
samedi 4 septembre, 2021 17:46:20

PS: With these wrong addresses the port also becomes ZERO. E.g. [e885:0db8:abcd:ef01::1]:0, there’s something seriously going wrong in program’s memory.

Anisse Astier (aastier)
lundi 6 septembre, 2021 16:56:01

Very interesting, thanks. Could you provide us with a pcap or tcpdump of the problem happening ? (privately if necessary) Are you sure the packets are coming from a Freebox ? The client ID is a good tip, but we’d be more certain if we had the source IPs for instance.

Buggy (bugbuster)
samedi 18 septembre, 2021 10:57:48

I can share the screenshots I’ve taken that show the “broken PEX IPv6” addresses and the IP addresses of the Freebox BitTorrent users from France (two different subnets for IPv4 and IPv6 pairs: AS12322). Again: I determined it was the Freebox peer by blocking connections to everybody else for a long time.
Additional notes: I have IPv4+IPv6 and this happened when I was a slow seeder and Freebox was a long-term leecher, connected for a very long time.

I do not have packet dumps: I will capture them the next time I find another Freebox user with a long-term connection to me. Encryption must be disabled correct? It can take me a long time because I’m not as active and in the past months I’ve only seen 2 Freebox peers. I had hoped you could test it since you have the hardware and software :)

How can I send you screenshots privately? You can send me instructions to the e-mail registered here. Yes, I understand Bittorrent (DHT) is a public network.

Marios Makassikis (mmakassikis)
samedi 18 septembre, 2021 12:48:19


The next firmware release will include a fix for this bug. Thanks for reporting it !