[Freedombox-discuss] FreeedomBox data leakage, firewall issues.

A. F. Cano afc54 at comcast.net
Thu May 2 20:11:46 BST 2024


On Thu, May 02, 2024 at 05:25:11PM +0200, Petter Reinholdtsen wrote:
> [A. F. Cano]
> > I have long noticed that there is usually some data going out of the
> > external interface.  I have always assumed it was housekeeping stuff,
> > such as dns.  However, Cockpit is now showing data going out at 1 Mbps
> > and receiving at 300-400 Mpbs.  Something is going on that looks very
> > suspicious.
> 
> It seem very different from mine, which is behind NAT-ing and only

I'm not behind NAT.

> available via pagekite.  As far as I can tell, only Tor and pagekite
> traffic is present when I run 'iftop'.  Did you try to press 'p' to get
> the port number displayed?  Any idea if it is TCP or UDP?  My 'sudo lsof

Aha!  All that traffic is from/to port 3478, which, according to this:

https://www.speedguide.net/port.php?port=3478

is what the STUN server uses.  This page says this means "Session
Traversal Utilities for NAT", but since I'm not behind NAT, do I really
need this running? It was my impression that it was required to use the
matrix synapse server, which I use all the time.  Furthermore, why is it
sending all that data when it's not in use?  No one is connected to the
matrix server.

Interesting...  After turning off the Coturn app, the transmitting has
gone to 0 but the receiving is still going strong:

fbx:3478                   => hosted-by.atakehosting.:22    0b      0b      0b
                           <=                            51.8Kb  58.0Kb  83.5Kb
fbx:3478                   => 20.198.76.220:16501           0b      0b      0b
                           <=                            11.6Kb  17.6Kb  21.0Kb
fbx:3478                   => 20.204.191.192:10065          0b      0b      0b
                           <=                            10.3Kb  14.1Kb  16.5Kb
fbx:3478                   => 20.235.10.172:11218           0b      0b      0b
                           <=                            10.9Kb  11.1Kb  10.3Kb
fbx:3478                   => 20.219.76.250:22798           0b      0b      0b
                           <=                            10.9Kb  10.8Kb  10.6Kb
fbx:3478                   => 20.235.52.217:16842           0b      0b      0b
                           <=                            10.7Kb  10.6Kb  10.5Kb
fbx:3478                   => 20.204.88.179:22948           0b      0b      0b
                           <=                            9.94Kb  10.5Kb  10.3Kb
fbx:3478                   => 20.235.88.156:18662           0b      0b      0b
                           <=                            10.3Kb  10.4Kb  9.68Kb
fbx:3478                   => 20.198.75.192:16897           0b      0b      0b
                           <=                            10.7Kb  10.3Kb  10.8Kb
fbx:3478                   => 20.198.105.102:29339          0b      0b      0b
                           <=                            10.5Kb  10.2Kb  10.5Kb
fbx:3478                   => 20.219.6.192:15243            0b      0b      0b
                           <=                            10.5Kb  10.1Kb  9.42Kb
fbx:3478                   => 20.235.53.133:28456           0b      0b      0b
                           <=                            10.3Kb  10.1Kb  2.95Kb
fbx:3478                   => 20.235.51.83:25582            0b      0b      0b
                           <=                            9.56Kb  9.49Kb  9.33Kb
fbx:3478                   => 20.235.147.234:11290          0b      0b      0b
                           <=                            10.1Kb  9.45Kb  9.33Kb
fbx:3478                   => 20.204.179.88:26048           0b      0b      0b
                           <=                            9.38Kb  9.30Kb  8.56Kb
fbx:3478                   => 4.213.68.43:10686             0b      0b      0b
                           <=                               0b   8.36Kb  9.98Kb
fbx:3478                   => 4.213.64.122:24385            0b      0b      0b
                           <=                            9.00Kb  7.12Kb  1.78Kb
fbx:3478                   => 20.235.54.175:27404           0b      0b      0b
                           <=                            7.88Kb  1.95Kb   499b

I can connect to the matrix server from my usual internal machine I use
for the video conferencing but of course there is no one slse at the
moment to conference with, so I don't know if the lack of the
STUN/Coturn server might or might not affect them.

> -i|grep EST|grep -v localhost' only show pagekite after I stopped tor.

Ok, after stopping the Coturn app, this command only shows privoxy,
sshd, apache2 and syncthing entries.  Very useful command.

The sshd entries all reflect the connections from internal machines, so
no problem here.

One privoxy entry is pointing to the mastodon server.  Since I have a
tab open for that, ok.  Others point to internal machines, so also ok.
One though points to 

privoxy    566165        privoxy    5u  IPv4 11129305      0t0  TCP fbx:45490->104.26.2.82:https (ESTABLISHED)

Per ipinfo.io this is in San Franciso, California.  As it is an https
connection, probably one of my open tabs.

One apache2 connection points to an internal machine, the other to:

pool-108-50-237-254.nwrknj.fios.verizon.net

Not sure what this is.  It's an https connection.  This web page doesn't
give much information beyond apparently not being dangerous

https://www.ipqualityscore.com/free-ip-lookup-proxy-vpn-test/lookup/108.53.237.254

Finally there are 2 syncthing connections:

syncthing 1005851      syncthing   19u  IPv4 10899136      0t0  TCP fbx:48456->162.212.157.128:22067 (ESTABLISHED)

This one is in Glenview, Illinois.  Not sure why syncthing is connecting
to the outside since all I wanted was to sychronize internal machines
and the phone when on internal wifi.

The other one is internal.

So, after stopping the Coturn app, connections seem much more
reaaonable.  I would still like to know what the coturn app was sending
where and why I keep receiving 300-400 Kbps on port 3478 and what all those
bits are.

In any case, thank you very much for replying.  You pointed me to the
culprit.  Now the FreedomBox is transmitting 10-15 Kbps and still receiving
about 300 Kbps on port 3478.

> -- 
> Happy hacking
> Petter Reinholdtsen

Augustine



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