I have configured a few VPNs on my Ubuntu notebook. Some of them are OpenVPN, and in fact they are fairly easy to configure.
However, sometimes I receive this error:

I wasn’t able to exactly identify the situation when this happens – it seems to be related to networking, and it happens more often when I log into my desktop with WI-FI connection, OpenVPN daemon starts, then I plug an ethernet cable.

SHORT ANSWER

A quick solution is simply to log out and log in again. It is simple but I don’t like it very much.

Other than that everything regarding VPNs on Ubuntu Desktop seems to be a bit of a mess. In the long answer you can find some more details regarding OpenVPN.

LONG ANSWER

In Internet you can find a lot of guides on how to set up an OpenVPN on Ubuntu Desktop. One simple and effective is Ubuntu’s Official: Help Ubuntu – OpenVPN. Anyway, most of the times everything is reduced to

to install a service, or

to install an extension to the Network Manager GUI.

However, the GUI option has some limitation – for example, you can only connect to one VPN at the time. If you have more than one VPN (and you can handle all routing problems with overlapping networks that can occur), you have to go with the service. To go with the service, you have to put all your OpenVPN configuration files, with extension .conf, in folder /etc/openvpn . Then (if your configuration files are correct, if your connection is ok, and a billion other ifs) if you restart openvpn service, you should see something like this:

That means that your VPNs are up and running.

However, if you have password authentication, for some reason, even if you have your credentials in a file connected to the configuration file, sometimes the service will hang, simply because the VPN restarts and it is waiting in background for a password. So, you have to restart the service.

But the agent of the first error it’s not this service. They are two completely different things. I think that this agent is something GUI related, for I meet this error only on the network manager GUI, and not with the service – which keeps running. However, it could just be that the service it’s still using WI-FI connection.

Unfortunately I have no real explanation for this and no real solution; just a quick workaround. It is a fairly complicated matter, which would require a lot of debug for a very simple task, and I don’t think it is worth the time.

Delete Windows Saved Network Password

by admin on

This very simple how-to can be used for all versions of Windows 7, Windows 8 and Windows Server 2008 . I didn’t test on Windows Server 2012

The most common situation it happens to me is: “OK, I have this network share. Let’s access with this user…ok it works. No, wait! This is the wrong user!!” or even “Let’s access with this user and save the password..NOOOOOO I didn’t check ‘Save Password!!!” And then I have to restart the PC and hope that it asks again for user and password.

After the 100th time I did something like this, I decided to learn how to make Widows forget saved network passwords.

SHORT ANSWER

In truth there’s ONLY a short answer. All you have to do is:

  • Start->Search programs and files
  • Type Credentials Manager
  • On the field Windows Credentials you should have one or more rows.

    Credential Manager - Summary

    Credential Manager – Summary

  • Click on the credential you want to remove
  • Click on Remove from vault

    Credential Manager - Remove from vault

    Credential Manager – Remove from vault

  • Now you can access again to the share you want to save and use the right credential and/or save them
  • By the way, if you want to change the credentials, you can click on Edit and change user and/or password. You cannot change the server (URL or IP).

    Credential Manager - Edit

    Credential Manager -Edit

I REALLY HATE those problems. It is only a way to make complex a simple thing.

Anyway, these are the symptoms.  Two NAS (Network Attached Storage), both with NFS and SAMBA shares. Both of them have public – passwordless – shares and private – password-protected – shares . The configuration files are IDENTICAL (except for share names). SAMBA and NFS version are the same. NFS works as expected. SAMBA has different behaviours in the two systems when accessed from a Windows client.

Let me expand this a bit. When accessing a public share, you should be able to put something like \\192.168.1.20\bigbrusArchve in Explorer and directly access the share content. No password asked, no username, nothing. When you access a private share (\\192.168.1.20\bigbrusPrivateArchive) you shouldn’t be able to access unless you have an allowed user and its SAMBA password (yes, samba, for it can be different from the OS one).

In my case, with the situation above, tryng to access via SAMBA from a Windows Server, one NAS behaved correctly (direct access for public share, password for private);the other one asked for password anyway, for any share, public and private. Empty user and password did not work. If I put “guest” as user and an empty password I could access only to public shares, but some programs and scripts which ran as different users (just as an example, IIS users for published websites) couldn’t, for a password was asked anyway.

SHORT ANSWER

There can be many causes to a SAMBA public share asking for a password. Most of them are misconfigurations. But given I had and identical NAS with identical configuration, this couldn’t be the problem.

It turned out that SAMBA seems to check permissions on the share’s subfolder. In my case I had to set permissions as “nobody:users” . If you have some other owner or group, samba will ask you a password, for not every folder in this share can be accessed using anonymous user.

My solution then was to execute:

that is: change recursively ownership of every file and folder in /network/share to nobody:users.

Note: you may need to change the user and/or the group according to your system.

LONG ANSWER

This post unfortunately is fairly technical; to explain every term and technology would require multiple ad-hoc posts, which I cannot write right now. Anyway, I’ll link some articles to go more in depth with these topics. Mostly are from Wikipedia: usually it is the best place to find some explanation.

Internet Cable Under The Ocean

by admin on

This is an amazing animation showing how manyinternet cables (mostly fiber) are there in the oceans – and where are they. In fact internet distribution network is an amazing topic, even if rather complex. Now I won’t talk about this; maybe sometimes I’ll write something.

In the meantime, enjoy this video:

Just so you know, this is how large a cable is. It can carry several tens of terabits per second.

Diver with oceanic internet cable.