The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘VPN’ Category

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OpenVPN somehow failed when tethering on the Android mobile hotspot from a new phone

Posted by jpluimers on 2023/04/07

A while after I got a new smartphone, I noticed that when my MacBook was connected over Wi-Fi to the mobile hotspot of my Android phone, the Tunnelblick connections over OpenVPN to my family members would not work. A telnet from the Android phone to the OpenVPN TCP port 1194 woud succeed, but not from the MacBook. Connecting from the phone using JuiceSSH to the OpenSSH endpoints at those family members would work too, so I was a bit flabbergasted.

In the end this seems to be a set of coincidences that fails in this particular setup, but I am not totally aware why.

The solution was to both re-configure the APN (Access Point Name) the smartphone uses to connect to the internet from ipv4/ipv6 to ipv4, and to reboot the phone.

For Dutch provider KPN Mobile, the APN is named internet and apparently changed default to ipv4/ipv6 without properly supporting ipv4. Note the configuration parameters are all lowercase, although they should be written IPv4 and IPv6.

Here are a few posts that got me on the right track (all via [Wayback/Archive] openvpn fails over android hotspot – Google Search):

Note that sometimes the MTU can cause similar failures:

Note too: some links to check for OpenVPN responding are below.

Various sites with (often different) APNs that KPN mobile supports:

There are quite a few APNs, some with firewall and/or proxy and/or compression, some with external IP address (which means your smartphone really needs a firewall).

–jeroen

Posted in Android Devices, Hardware, Network-and-equipment, OpenVPN, Power User, VPN | Leave a Comment »

Dave Anderson on Twitter: “Cool minor @Tailscale moment: I’m recommissioning a server that got moved from a different network, so all its network config was wrong, and generally I couldn’t get at it over the network, only IPKVM console. But then my `ping` over Tailscale started working?!” / Twitter

Posted by jpluimers on 2023/04/04

Wow, I wrote about Tailscale a few times before, and it is still on my research list, but this is a very compelling reason to use it. [Archive] Dave Anderson on Twitter: “Cool minor @Tailscale moment: I’m recommissioning a server that got moved from a different network, so all its network config was wrong, and generally I couldn’t get at it over the network, only IPKVM console. But then my ping over Tailscale started working?!” / Twitter

I archived the thread so it becomes easier to read: [Wayback/Archive] A readable Thread by @dave_universetf Says Cool minor @Tailscale moment: I’ – UnrollThread.com.

The core are these three tweets:

Turns out, IPv6 autoconfiguration is what happened. Sure, v4 configuration was entirely wrong (it was trying to connect to wifi, via a wifi dongle that was no longer installed, and wanted to talk to a DNS server that doesn’t exist any more), but eno1 had a cable plugged in!
The server noticed IPv6 router advertisements, went “I’ll have some of that”, and got global IPv6 connectivity automagically. IPv4 and DNS were still down though, so all it had at this point is the ability to send/receive IPv6 packets.
So, how did Tailscale get from there to a working setup? It still needs to contact https://t.co/hEs4S8qvTw to get a network map, and still needs to talk to DERP servers to get p2p tunnels working outside the LAN. Enter bootstrap DNS!

It means I have to re-read Source: Some links on Tailscale / Wiregard, especially the [Wayback] How Tailscale works · Tailscale bit, then decide how I want to organise my infrastructure to run parts under Tailscale (I have the impression it is a peer based set-up, not router based).

Then I have to read [Wayback/Archive] IPv4, IPv6, and a sudden change in attitude – apenwarr of which the conclusion is this:

IP mobility is what we do, in a small way, with Tailscale’s WireGuard connections. We try all your Internet links, IPv4 and IPv6, UDP and TCP, relayed and peer-to-peer. We made mobile IP a real thing, if only on your private network for now. And what do you know, the math works. Tailscale’s use of WireGuard with two networks is more reliable than with one network.

Finally I need to not just read it, but understand all it (:

Or maybe I should ask Kris, as I got here through:

I saved Kris’ message thread here at [Wayback/Archive] Thread by @isotopp on Thread Reader App – Thread Reader App.

An OK translation is at [Wayback/Archive] Thread by @isotopp on Thread Reader App – Thread Reader App.

–jeroen

Posted in Hardware, Network-and-equipment, Power User, Scoop, Tailscale, VPN, Windows, Wireguard | 1 Comment »

I had some Windows ATOM issues before, but this beats them easily

Posted by jpluimers on 2022/10/19

I’ve had some issues with Windows ATOM tables filling up, but nothing like this security bypass:

A new Windows code injection technique, atombombing, which bypasses current security solutions.

Source: AtomBombing: Brand New Code Injection for Windows – Breaking Malware [WayBack] with source code at BreakingMalwareResearch/atom-bombing: Brand New Code Injection for Windows

Note that since writing the first draft, the above AtomBombing article moved via Wayback: blog.ensilo.com to [Wayback/Archive.is] AtomBombing – A Brand New Code Injection Technique for Windows | FortiGuard Labs.

Read the rest of this entry »

Posted in Development, FortiGate/FortiClient, Hardware, Network-and-equipment, Power User, Security, Software Development, VPN, Windows, Windows 10, Windows 7, Windows 8, Windows 8.1, Windows 9, Windows Development, Windows Server 2000, Windows Server 2003, Windows Server 2003 R2, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, Windows Vista, Windows XP | Leave a Comment »

Since about 5 months now, there has been a new Chocolatey package maintainer for OpenVPN

Posted by jpluimers on 2022/08/26

Last winter, I discovered that the OpenVPN version on Chocolatey was really old: it had not been updated since 2019.

Most  Chocolatey maintainers are volunteers and sometimes the burden can become too large. Back then the maintainer was [Wayback/Archive] Chocolatey Software | wget, but luckily [Wayback/Archive] Chocolatey Software | dgalbraith has stepped in and in March 2022 bumped the version from [Wayback/Archive] Chocolatey Software | OpenVPN 2.4.7 to [Wayback/Archive] Chocolatey Software | OpenVPN – Open Source SSL VPN Solution 2.5.4 and kept maintaining (currently there is [Wayback/Archive] Chocolatey Software | OpenVPN – Open Source SSL VPN Solution 2.5.7).

Read the rest of this entry »

Posted in *nix, *nix-tools, Chocolatey, Hardware, Network-and-equipment, OpenVPN, Power User, ssh/sshd, VPN, Windows | Leave a Comment »

Perkeep lets you permanently keep your stuff, for life.

Posted by jpluimers on 2022/03/30

For my link archive: [Wayback] Perkeep

Via [Wayback] bradfitz – Joining Tailscale: Simplifying Networking, Authentication, and Authorization (which has many interesting linkis, including [Archive.is] bradfitz/homelab: Brad’s homelab setup)

–jeroen

Posted in Cloud, Hardware, Infrastructure, Network-and-equipment, Perkeep, Power User, Storage, Tailscale, VPN, Wireguard | Leave a Comment »

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