ubuntu – Cannot apt-get update from inside my docker container if connected to bridge network

I am trying to understand, why I am unable to run apt-get update from within my docker containers, either debian:latest or ubuntu:latest.

  • I am able to ping or other address from within the container
  • I am able to ping google.com or other domains from within the container
  • apt-get update works if I start the container with --network host
  • apt-get update does not work if the container is connected to the default bridge network or any other user defined network with adapter set to bridge
  • The host is a virtual machine managed by openstack
  • Everything works as expected on my computer (not openstack, not virtual)

apt-get update will time out with:

root@66230c3e7572:/# apt update
Err:1 http://deb.debian.org/debian buster InRelease                           
  Connection failed (IP: 80)
Err:2 http://security.debian.org/debian-security buster/updates InRelease
  Connection failed (IP: 80)
Err:3 http://deb.debian.org/debian buster-updates InRelease              
  Connection failed (IP: 80)
Reading package lists... Done
Building dependency tree       
Reading state information... Done
All packages are up to date.
W: Failed to fetch http://deb.debian.org/debian/dists/buster/InRelease  Connection failed (IP: 80)
W: Failed to fetch http://security.debian.org/debian-security/dists/buster/updates/InRelease  Connection failed (IP: 80)
W: Failed to fetch http://deb.debian.org/debian/dists/buster-updates/InRelease  Connection failed (IP: 80)
W: Some index files failed to download. They have been ignored, or old ones used instead.

I would like to find out why apt-get udpate is not working while I’m connected to any bridge network on the virtual machine. So any hints on how to debug this problem are very appreciated.

unity – Dynamic bridge via joints

When a new object is added to the bridge, the bridge shakes violently, and when objects are added even faster, it breaks.

I’ve tried changing mass and changing time step, but that doesn’t solve the problem.

enter image description here

Code for adding a new object:

Rigidbody _last;

GameObject _prefab;

void Update()
    if (Input.GetMouseButtonDown(0))
        var go = Instantiate(_prefab);
        var fj = go.GetComponent<FixedJoint>();
        fj.autoConfigureConnectedAnchor = false;
        fj.connectedAnchor = new Vector3(0f, 0f, -2f);
        fj.connectedBody = _last;
        _last = go.GetComponent<Rigidbody>();

The first cube is kinematic.

enter image description here

How can you solve this?
Thanks for help

photo editing – Why do I lose my edits after creating HDR raw files in Adobe CC Bridge ACR and enhancing them,

I’m a 20 year user of Photoshop and never had this happen before. After creating HDR raw files in Adobe CC Bridge ACR and enhancing them, I lost all of the edits after moving the files (note: the xmp files are still there). I didn’t even move them out of the folder, I just sorted the folder by “Type” so that all of the newly created HDR files would be put in one place and easily grabbed to move to a “selected folder” for image processing. I’ve deleted Adobe Bridge and Photoshop and re-installed. I did a “Ctrl+Alt+Shift” to reset the preferences for Bridge and that didn’t do anything. I’m at a loss. This has been happening to the last 6 projects I’ve edited and then I have to re-edit and not move them in anyway in order to process into jpegs. Once I move them, the edits go away, but not all the edits. On some of the images, some remain. Sometimes it happens to only part of the images that are edited. There is no rhyme or reason. I don’t know what else to do?

powershell – Pinging internet addresses and other machines in the same VM subnet, from inside Docker EE Windows Container with L2 Bridge

I have the following setup: 2x Windows Server 2019 VM on Azure in the same virtual network. One of them is a Docker host, and its name is SRV-ONE. The other one is named SRV-TWO. I’m using default Azure-provided DNS, and I can ping each other by name without issues. They are on a subnet, having IPs provided via DHCP by Azure (Default gateway is

However, there are two requirements: the first one is that our containers should be capable of reaching not only the Docker host but also other machines in the same network. So, I configured the Docker daemon.json to search for the suffix used by the VMs and to not create the default NAT, so I could create my L2 Bridge because it is better to work with it when running virtualised Docker hosts on Azure.

    "dns-search": ("azuregeneratedhash.xx.internal.cloudapp.net"),
    "bridge": "none"

The second one is that the containers need access to Azure IMSD API(Metadata Service, at, which is non-routable. So, as a test, I should be able to retrieve Metadata information from a VM through something like this:

Invoke-RestMethod -Headers @{"Metadata"="true"} -Method GET 
    -Proxy $Null 
    -Uri ""`

I’m using Azure Global DNS to provide name resolution, which is My Docker Network creation command looks like this:

docker network create -d l2bridge --subnet --gateway 
    -o com.docker.network.windowsshim.dnsservers=""
    -o com.docker.network.windowsshim.enable_outboundnat=true MyL2Bridge

With this setup, I’m able to do the following with a regular “disposable” container:

  • Ping the Docker Host (SRV-ONE) by name, without using FQDN
  • Get containers to use dynamically assigned IP addresses from the same subnet as the VMs
  • Get Metadata information about the Docker host through Azure IMSD API
  • Have Name resolution working (SRV-TWO and google.com names are being resolved OK).

What doesn’t work:

  • Ping SRV-TWO or google.com from a container doesn’t work, even though I have the enable_outboundnat=true flag set when creating the docker L2 Bridge network. The names get resolved flawlessly. Reaching them is another story.

How could I reach internet addresses and also other VMs inside this subnet with this setup?

network – OpenVPN bridge – using same interface for internet connection

For setting a vpn connection in bridge mode using openvpn, the documentation of OpenVPN for configuring a bridge mentions that the OpenVPN client must have at least two Ethernet interfaces, one connected to the Internet, one connected to the private LAN segment, and it remarks that we should never bridge a TAP interface with the same ethernet interface you use to connect to the internet, as that would create a potential security hole.

Why this configuration creates a security hole?

Ethernet Bridging

probability – Maintain direction of effect of subset in a bridge chart even when it is reversed as part of the larger population

This is to do with weighted odds. I think this is best to show with an example:

Day 1 Day 2 Bridge
Item Weighting Odds Weighting Odds
New 0 0% 500 0.5% 0.02%
Remain 14000 2.11% 13000 2.12% -0.02%
Gone 300 3% 0 0% -0.04%
Total 14300 2.13% 13500 2.06% -0.07%

So I have the following bridge chart values:

2.13% -> +0.02% -> -0.02% -> -0.04% -> 2.06%

The problem I have is that the middle bold number (the weighted difference between the populations ({13000 * 2.12% / 13500} – {14000 * 2.11% / 14300})) in the bridge is negative, even though the Odds for that subgroup is a positive movement (2.11% -> 2.12%).

What calculation should I be doing, I assume that in order to show that middle group as a positive movement the negative movement of ‘Gone’ will have to be enhanced. I want to show that from Day 1 to Day 2 it went from 2.13% -> 2.06% but I also want to show that ‘Remain’ went up in this bridge.

Is this even possible to show in a legitimate way?

network – Thunderbolt Bridge not connected

I need to transfer a lot of files between two 2019 MacBook Pros, but when I connect them using a Thunderbolt cable, the bridge never connects and assigns an IP via DHCP.

I tried manually assigning an IP and subnet mask to both of them, but still can’t connect them.

What is wrong here?

mysql – How do I do query search on database with multiple tables, including a bridge table?


The link below shows highlighted columns that I want to be selected in a query where the mining_water_inventory_id is common.
The problem is my teacher has only taught me simple queries such as

SELECT * FROM Customers
WHERE Country='Mexico';

but I have no idea how to select the highlighted columns by mining_water_inventory_id.

pr.probability – Probability that a $d$-dimensional Brownian bridge is greater than a given parameter

Let $(W_t)_{tin(0,T)}$ be a Brownian bridge such that $W_0=a$ and $W_T=b$, the probability that $forall tin(0,T),W_tgeqslant x$ given the parameter $xleqslantmin(a,b)$ is well known :
$$ mathbb{P}(forall tin(0,T),W_tgeqslant x)=1-e^{frac{2(x-a)(b-x)}{T}} $$
(see Probability of general Brownian (or non) bridge to be higher than given parameter? for a proof). My question is : Is there a generalization of this result for $d$-dimensional Brownian bridges ? That is, if $(W_t)_{tin(0,T)}$ is a $d$-dimensional Brownian bridge such that $W_0=ainmathbb{R}^d$ and $W_T=binmathbb{R}^d$, what is the probability that for all $tin (0,T),|W_t|geqslant x$ where $x>0$, for a convenient norm $|cdot|$ whether it is $|cdot|_2$, $|cdot|_{infty}$ or any norm that makes it possible to compute/approximate.

In the case where $|cdot|$ is the euclidean norm of $mathbb{R}^d$, $tmapsto|W_t|$ is a Bessel process which is well known but I can’t find any related paper tackling the above probability.

linux networking – How can I set up a layer 3 bridge using Proxy ARP such that http requests can be made to the inside/proxied host’s IP successfully?

Currently I am using a Raspberry Pi to bridge an ethernet connected printer to wireless internet and have used DNAT successfully to give the printer internet access, manually forwarding the printer’s port 80 to the Rpi’s wlan0 interface port 80 along with other needed ports to access the printer using outside hosts. I’ve also been able to use Proxy ARP so that the printer’s static IP address is visible on the network, the Pi responding to ARP broadcasts on the printer’s behalf and proxying ARP requests for the printer. What I would like to do is combine the functionality of the DNAT approach with the IP separation provided by Proxy ARP.

The problem is that I cannot figure out how to seamlessly accomplish the needed forwarding/spoofing with the Rpi so that instead of directing requests to the Pi’s port 80, outside hosts can make requests using the printer’s IP directly even if it’s on a different subnet, say, to access the http page.

Is it possible to accomplish this routing in tandem with Proxy ARP? Are there other approaches that are better suited for this arrangement, or could IP aliases alongside DNAT accomplish this illusion that the printer’s IP and active ports are also present on the network/another network?