Tomato OpenVPN client assigned for specific computers

Setting Redirect Internet traffic to “Policy Rules” opens a table where you can specify which computer goes through VPN and which ones uses direct connection. Leave the destination IP unspecified and it’ll pick the 0.0.0.0 as intended

However, there’s a logical trap when you blindly follow instructions setting “Accept DNS configuration” to “Exclusive” as given by most instructions assuming all computers go on the network through VPN. Setting it as “Exclusive” means even the computer not intending to use VPN will still need to go through your VPN provider’s DNS! For slow VPN connection, this will be painfully slow for ALL computers! Set it to “Relaxed” instead.

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Not missing Windows after trying Ubuntu Cinnamon Remix

Given that I grew up as a power DOS/Windows user, I often have gripes about how frustrating Linux is and they were almost never ready for people who just want to get common things done by intuitively guessing where the feature is (therefore having to RTFM or search the web for answers).

I deal with HP/Agilent/Keysight instruments a lot and appreciated their effort put on user experience (UX) design. It’s not that user who’s stupid if they have to dig through 5+ levels of menu buttons to measure a Vpp (peak to peak voltage) and the software aren’t smart enough to default to the only channel in use. That’s what Tektronix did to their nasty user interface and raised a generation of Stockholm Syndrome patients who keep buying Tek because they are traumatized by the steep learning curve and would rather walk on broken glass than having to learn a new interface from another vendor (that’s called vendor lock in).

I certainly appreciate Cinnamon desktop environment (came with Linux mint) designers willing to not insist on the ‘right way of doing things’ and follow a path that’s most intuitive for users coming from a Windows background.

The last time I used Linux Mint was 19. There’s still quite a lot of rough edges. Some services got stuck (time-outs) right out of the box and systemd went through slowly. It’s just not fast and responsive. When I tried it again when Mint 20.1 was released, my old i3 computer boots to the GUI in 5 seconds and I was hell of impressed. The icons and menus are also now sized balanced proportions like Windows (can’t stand the big and thick default menu-item fonts like Ubuntu).

However, there’s one big impeding factor for me to make Linux Mint my primary computer: the packages repositories are one generation behind Ubuntu (the most widely supported distro)! Software often have bugs that the developers solved, living with old, ‘proven’ software slows down the iterative process.

I’ve been through hell trying to access Bitlocker volume with Linux Mint 20.1 as not only it doesn’t work right of the box like Windows, I’m stuck with a command line dislocker that doesn’t integrated with the file manager (like Nemo). The zuluCrypt available with Mint 20.1 is too old to support Bitlocker properly. Trying to upgrade it to 6.0 has Qt dependencies which is unsolvable. I was able to download the unsanctioned old revision in debian package but there’s more unsolvable dependencies.

The alternative option of compiling from the source is met with more dependencies fuckery and now the restrictive Mint repository might not have the exact version of the compiler required by the source code package. Aargh!

I was about to give up Linux Mint and install Ubuntu and try to hold my nose changing the desktop to Cinnamon. Luckily I’ve found somebody who read my mind: there’s Ubuntu Cinnamon Remix!

Not only Ubuntu Cinnamon Remix supported Bitlocker right out of the box (no need to fuck with zuluCrypt which doesn’t integrate with the file explorer anyway)! Most of the defaults make sense, buttons are often where I expect them to be. Even Win+P key works identically! The names/lingo are close to Windows whenever possible, and honestly the default Yari theme is visually slightly more pleasing than Windows as it makes very good use of the visual spaces!

Here’s a few transition tips

Windows Ubuntu/Cinnamon
WallpaperBackground
Device Manager(No equivalent) Install hardinfo for System Information
Task ManagerSystem monitor
Windows KeySuper Key
ShortcutLauncher
Lingo
Windows Linux
Foobar2000deadbeef
Notepad++notepadqq
Greenshotksnip
Apps and its near equivalents

I use Winsplit-Revolution in Windows (old version is freeware) that uses the numeric keypad to lock the window to the 9 squares grid using Ctrl+Alt+{Numpad 1-9}. Save the keyboard shortcuts in case if you want to install it again on another computer:

dconf dump /org/cinnamon/desktop/keybindings/ > dconf-settings.conf
dconf load /org/cinnamon/desktop/keybindings/ < dconf-settings.conf

There’s no Ctrl+Shift-Esc key which I often use to call Task Manager (called System monitor). I had to make the shortcut as well to feel at home.

WindowsLinux
(Explorer) Alt-D for address bar(Nemo) Ctrl+L

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HP 54502A Datasheet typo about AC coupling

The cutoff frequency of 10Hz on the datasheet is a typo. Better scopes at the time claims 90Hz. 10Hz is just too good to be true.

Found the specs from the service manual:

Don’t be fooled by the -3dB cutoff and ignore how wide the transition band can be (depends on the filter type and the order). Turns out this model has a very primitive filter that AC couple mode still messes square waves below 3kHz up despite the specs says the -3dB is at 90Hz. You better have a 30+ fold guard band for old scopes!

Remember square wave pulse train in time domain is basically a sinc pulse centered at every impulse of the impulse train in frequency domain superimposed. Unless you have a tiny duty cycle (which is not the case for uniform square waves, they are 50%), the left hand side of the sinc function at 1kHz fundamental still have sub-1kHz components that can be truncated by the AC coupling (high pass filter).

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Qemu for Windows Host Quirks

I’m trying to cross compile my router’s firmware as I made a few edits override the update DDNS update frequency. Turns out it doesn’t work on the latest Linux so I’d need to run an older Ubuntu just to keep it happy.

RANT: Package servers keeps pulling to rug on outdated linux is frustrating. Very often developers didn’t make a whole installer it so we are often wedged between downloading a package at the mercy of its availability from package managers and their servers or compiling the damn source code!

With the promise that Qemu might have less overhead than Hyper-V or VirtualBox (indeed it observably is), I tried installing Qemu on Windows host and it turned out to be a frustrating nightmare.

RANT: Linux is not free. The geniuses did the most sophisticated work for free but users pay time and energy cleaning after them (aka a support network dealing with daily frustrations) to made these inventions useable. There’s a company that does the clean up to make BSD (same umbrella as Linux/Unix) useable and made a lot of money: it’s called Apple Computers since Steve Jobs return.

qemu is just the core components. System integration (simplifying common use cases) are practically non-existent. Think of them as the one who produced an ASIC (chip) and the end-user happens to be the application engineers. There’s a few tutorials on qemu Linux hosts for moderately complex scenarios, but you are pretty much on your own trying to piece it altogether for Windows because there are some conceptual and terminology differences. The man page --help for the qemu’s Windows host’s VM engine was blindly copied from the Linux hosts counterpart, so it tells you about qemu-bridge-helper which is missing.

I stupidly went down the rabbit hole and drained my time on qemu. So I documented the quirks to help the next poor sap who has to get qemu running on Windows 10 host efficiently over Bridged-Adapter (VirtualBox lingo) networking mode.

  • Preparation work to get HAXM accelerator set up
    • Release VT-d (hardware assisted virtualizations) so HAXM can acquire it
      • You’ll need to remove Hyper-V completely as it will hoard VT-d’s control
        • Windows Sandbox and Windows Subsystem for Linux (WSL2) uses Hyper-V. If you just unchecked Hyper-V in Windows Optional Features leaving any of these 2 on, Hyper-V is still active (it only removes the icons)
    • HAXM v7.6.6 not recognized by qemu on clean install. Install v7.6.5 first, then remove it and install v7.6.6. Likely they forgot a step in v7.6.6’s installer
    • Turn on optimization by: -accel hax
  • Command line qemu engine
    • qemu-system-{architecture name}.exe is what runs the show
    • qemu-system-{architecture name}w.exe is the silent version of the above engine. Won’t give you a clue if something fails (like invalid parameters)
    • qemu-img create -f {format such as vhd/qcow2} {hard drive image name} {size like 10G}
  • QtEmu sucks, and they lack any better GUIs out there!
    • It’s basically a rudimentary command line’s GUI wrapper
    • It only has user mode (SLIRP) networking (default)
    • It’s not maintained actively so it doesn’t keep up with the parameter syntax changes (i.e. can generate invalid combinations)
    • Since it uses the silent (with a w suffix) engine, likely to avoid a lingering command window, it also won’t tell you shit and why if something fails. It just ignores you when you press the start button unless all the stars align (you got everything right)
  • Basic command line parameters
    • Set aside 10G for the VM: -m 10G
    • 1 core if unspecified. Number of available threads (in hyper-threaded system) show up as # of processors. It’s referring to logical processors, not physical cores.
      • Windows: -smp %NUMBER_OF_PROCESSORS%
      • Linux: -smp $(nproc)
    • Attach virtual hard drive: -hda {virtual hard drive file name}
    • Attach optical drive (iso): -cdrom {iso file}

I typically want Bridged-Adapter option from VirtualBox, which means the virtual NIC plugs into the same router as the host and just appears as another computer on the same network as host. This is broken into a few components in qemu and you have to manage them separately. Great for learning about how Bridged-Adapter really works, but a lot of swearwords coming from people who just want to get basic things done.

Networking in QEMU is another can of worms if you deviate from the default SLIRP (user mode). I figured out how to work it, but the network bridge is faulty and it keeps crashing my windows with BSOD on bridge.sys with varying error tag. I have short glimpse of it working if I move very fast. Looks like the TAP driver is corrupting the memory as the bridge became very erratic that I see error messages deleting it and have persistent BSOD when the bridge starts after the VM hanged at the TAP bridge on boot.

I listed the steps below to show what should have been done to get the Bridge-Adapter (VirtualBox) equivalent function if there are no bugs in the software, but hell I’m throwing qemu for Windows to trash as it’s half-baked.

First, of all, you need to install OpenVPN to steal its TAP-Win32 virtual network card. It’s not VMware or Virtualbox that it’s part of the package. Qemu didn’t care to tightly integrate or test this driver properly.

Then you’ll need to bridge the “TAP-Windows Adapter (V#) for OpenVPN” with the network interface you want it to piggy back on.

The name of the TAP adapter is what you enter as ifname= parameter of the tap interface in qemu command line. You have to tell qemu which specifically interface you want to engage in. I named the virtual network card as ‘TAP’ above. After bridging it looks like this:

You are not done yet! The bridged network (seen as one logical interface) is confused and it won’t be able to configure with your physical network card’s DHCP client. You’ll have to go to the properties of the Network Bridge and configure the IPv4 with static IP.

You can use ipconfig /all to find out the relevant adapters acquired DHCP settings and enter it as static IP. Coordinate with the network administrator (can be yourself) to make sure you own that IP address so you won’t run into IP conflict if you reboot and somebody took your IP.

After these are all set up the parameter to add to qemu call is:

-nic tap,ifname=TAP

There are complicated settings like -net nic and -netdev -device. These are old ways to do it and have bloated abstractions. -nic switch combined them into one switch.

Then welcome to the world of Windows 10 bridge.sys crashing frequently and you might get a short window of opportunity that it boots and ifconfig acquire the IP address settings from your router (or network the physical adapter is on)’s DHCP server.

It’s like a damn research project finding out something is technically feasible but definitely not ready for production. Welcome to FOSS jungle!

Postscript: I put Hyper-V back and realized it’s insanely slow with Linux Mint as it does not support hardware graphics acceleration. It’s night and day of a difference. Qemu is fast, but it crashes on Windows 10 if I bridge the adapters!

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Aria2 WebUI Notes

Aria2 is a convenient command line downloader that works like curl/wget on http/ftp, but it also support many other protocols, and it aria2 natively multipart download!

Instructions for Aria2 on Entware hosted by Lighttpd (defaults to Port 81): https://www.snbforums.com/threads/aria2-webui-on-asuswrt-merlin.63290/

Instructions for Nginx on Entware (defaults to Port 82): https://hqt.ro/nginx-web-server-with-php-support-through-entware/

Instructions for Aria2 on Entware: https://hqt.ro/aria2-download-manager-through-entware/

There are some minor details that changed.

# Install the base (core) software first
# This example is for entware
opkg install aria2

# Download the package from Github zip to /opt/tmp
wget -c -O /opt/tmp/webui-aria2.zip https://github.com/ziahamza/webui-aria2/archive/master.zip --no-check-certificate

# Make sure you have some web server installed (nginx, httpd, apache, etc.)
# Nginx HTTP server instructions
# https://hqt.ro/nginx-web-server-with-php-support-through-entware/
# Make sure you know what {Webroot} is
# for Nginx, {Webroot} is /opt/share/nginx/html

# Unpack to the zip file at /opt/tmp and clean up the zip
unzip /opt/tmp/webui-aria2.zip -d /opt/tmp/ && rm /opt/tmp/webui-aria2.zip
# Move/rename to desired location
mv /opt/tmp/webui-aria2-master {Webroot}/aria2

Nginx defaults to port 82 (change it to where you set your web server). The WebUI can be accessed at http://your_server_here:82/aria2/docs.

/doc is inconvenient, so I created a redirection by placing this index.html under aria2’s root folder:

<meta http-equiv="Refresh" content="0; url='./docs'" />

The RPC host breaks out of the box because the you’ll need to make a few adjustments to /opt/etc/aria2.conf before you can start the service without crashing it (so the WebUI of course will complain with a lot of cryptic error messages):

# Basic Options
dir={Change it to a viable folder that has enough space if /opt/var/aria2/downloads
 is is not big enough}

# RPC Options
# Unless you want to get a certificate, you'll need to use unsecure mode:
rpc-secure=false
# Change your rpc-secret to be matched in "Connection Settings" in the WebUI
rpc-secret=whatever_passphrase_you_like

After you get the config file correct

# Start the installed aria2 service 
$ (the package already have a service wrap over aria2c)
# aria2 seem to assume it's port 81 so the init.d script has a "S81" prefix, but aria2 does not control the port, where you put the WebUI in http. So it's just a cosmetic filename naming convention.
/opt/etc/init.d/S81aria2 start

If the service wouldn’t start (some bad configs might have the service reported as “done” and after you check again in a second with “S81aria2 check“, it’ll report as “dead”. You can debug by looking at what went wrong at /opt/var/log/aria2.log. That’s how I figured I need to turn off “rpc-secure” parameter.

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Mailpile Installation Notes

There’s a powerful Gmail web interface replacement for your regular mail hosted anywhere called Mailpile. Think of it as Thunderbird but hosted like a web page. There are a few things I liked about in the process of freeing myself from Gmail:

  • Free to use any email (storage) services and not tie your client to it
  • View multiple accounts at the same time (NextCloud won’t do it)
  • Very clean, concise interface that makes sense (Gmail users will be comfortable with it)
  • Very security and privacy conscious with attention to details! It even encrypts your local email cache and search index if you want to (performance penalty)
  • Excellent email setting autodetection. Just type your email account and everything’s set up for you!

The only downside is that the documentation is a little lacking. There are a few concepts that are not explained that’d confuse and scare users away. That’s why I’m explaining it here.

  • This is a headless service where the interface is webpage you access on a web browser.
  • It’s originally designed to install and run as a local web server where you access mailpile.
  • Call mailpile (can create a shortcut) and it’ll try to launch the correct page for the mailpile client.
  • Mailpile does not maintain a separate user registry: it uses the hosting computer’s native user manager
  • Log into your mailpile using the user account name of the computer where mailpile is installed!

Advanced concepts

  • Install multipile instead if you want other computer to access the headless service
  • You’ll need login to the computer that hosts the headless mailpile and run mailpile AS the user you want to setup once to establish the account before use.

Download and installation instructions:

# Currently there's only Debian-like distributions (because it uses apt-get)
# These instructions do not assume direct root account. Use sudo instead

# Install pre-requisite packages: curl apt-transport-https gnupg
sudo apt-get update && sudo apt-get install curl apt-transport-https gnupg

# apt-key add {contents of the package signing key provided by mailpile.is)
curl -s https://packages.mailpile.is/deb/key.asc |sudo apt-key add -

# Register mailpile.is's package server with Debian apt package manager
echo "deb https://packages.mailpile.is/deb release main" |sudo tee /etc/apt/sources.list.d/000-mailp.list
# NOTE: Official instruction says 000-mailp instead of 000-mailp.list 
#       You need to have some file extension as apt-get checks

# Multipile (mailpile-apache2) = Mailpile + (allowing access from other computers through apache)
sudo apt-get update && sudo apt-get install mailpile-apache2

# You'll need to run mailpile as the user once to establish your account with mailpile before use
mailpile
# If you are on terminal interface instead of web interface, enter 'setup' at mailpile prompt:
> setup
# Follow the instructions on the web interface for setup if you do not use terminal mailpile client interface

Additional Resources: https://greenpark-code.github.io/Mailpile_tutorial/

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Use old email clients (like outlook express and Windows Live Mail) with SSL email servers after TLS 1.0/1.1 support ended

My email service provider has recently pulled the plug on TLS 1.0/1.1 support as they reached end-of-life. This means old email clients not written for TLS 1.2 and above will not work when it tries to connect to the server with SSL support!

Google did this in 2014 but offered a compatibility option called “allow less secure clients”. Back then I didn’t know it means TLS 1.0/1.1 until I learned it the hard way when my shared hosting email provider pulled the plug on the old TLS protocols and I scrambled to figure out my email stopped working with cryptic IMAP errors (like suggesting my computer might be lacking memory, which is not true).


Stunnel config that needs to be changed from defaults. If stunnel was installed by entware (opkg), the config file is in /opt/etc/stunnel/stunnel.conf.

  1. Disable (comment out) drop privileges
  2. Remove the [dummy] section since we are going to set up sections for each (server, port) pair. stunnel won’t start without any port forwarding sections.
  3. It already has an [imap] section that’s commented out. Change the local port number and the target server url:port to your liking. Do [pop] if you use POP3 email instead of SMTP
  4. Do the same by adding a [smtp] section for outgoing email

Can look at the log by just executing stunnel. Use Ctrl+C to quit monitoring the logs.

Of course you want to make sure the stunnel service/server is always started on boot. If you are using entware (or jffs scripts) for your router, add the call to stunnel to /jffs/scripts/post-mount and make sure you set the script to executable so it’ll run:

#!/bin/sh
...
stunnel

Note that it’s post-mount because entware packages are installed on persistent storage (like USB drive or SD card in your router) that needs to be mounted before the files can even be read.

Remember to go to your old email client and change the email server address to computer running stunnel service (can be the same computer as the client, a raspberry pi, or a router)

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Namecheap DDNS does not work in Asus Merlin (Tomato) Firmware until 384.7_2

My router only supported Merlin (Tomato) firmware up to 380.70_0 (2018-04-08) and there are no more updated from that branch.

Turns out the Namecheap DDNS client is not working. I searched its source code at Github for “Namecheap” to see if I can fix the HTTP 400 error (seen in router log) using “in:file” hoping to see if I can fix the bug myself (since it’s just a simple REST API, aka URL call) command and found this:

It means Asuswrt-Merlin (Tomato)’s firmware’s Namecheap DDNS service is broken UNTIL 384.7_2, which is for newer routers than what I have.

I compared the “namecheap” keyword search for the two versions and it seems like they are written very differently, so it might not be worth the effort to fix the obsolete Merlin branch. Doing a bit of additional search and discussions about John’s Merlin fork from the early days are still updated until 2019-04-17 :

It took me a while to find John’s forum post to get to the said 2019-04-18 release. The download link he provided has more updates up to Update-44EA (2020-07-12) and it still worked on my old router, so it’s not just the Update-39L3 previously discussed in the forum:

Do not get discouraged when John’s Merlin fork says version 374.43 instead of 380 (a lower number). All updates, even the latest one from John still use 374.43, which I suppose it’s to mark when the two code branches part ways. It’s not an older version.

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To tough bargainers:

This meme is spot on about my expertise in HP/Agilent/Keysight Infiniium Oscilloscopes. It might take me 30 minutes to put on the automation I’ve created to fix a specific issue, but nobody with just one non-functioning unit in front of them can figure out the right steps even if they worked on it for months. Writing the automation itself turns out to be the least of the bulk, and it’s still more time than one is willing to spend writing the scripts or performing the undocumented procedures manually.

Many of my know-hows were acquired to be used once or twice. I solve problems that are not seen before. I always start with doing due diligence researching what has been done, rather than jumping to reinvent the wheel. If I confirmed that it’s an unsolved problem, I’ll start inventing.

Once I figure out the details I often automate the workflow, document it, and move on to something else.

That’s why for consulting, I often quote high hourly rate for the first few hours and taper it down for more complex projects (keeping the project short). It’s to make sure we don’t have incentives to waste each other’s time and focus on solving your problem as fast as I can figure it out.

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Off the Matrix Notes

Namecheap Shared Hosting

  • Free Dynamic DNS with domain (Namecheap has a free Windows client. Use zoneclient for Linux)
  • Email (IMAP): usese Maildir (for those who need migration)
  • Contacts: CardDav (use DavX5 adapter on Android)
  • Calendar: CalDav (use DavX5 adapter on Android)
  • Notes/Tasks: NextCloud (can sync with NextCloud’s built-in CalDav server)
  • Blog: WordPress
  • And of course, your own website!

VPS Hosting

  • NextCloud has File-On-Demand (like OneDrive) called Virtual File System (VFS)
  • YunoHost: easy to use modular self-hosting
  • UBOS Linux: distro for self-hosting. Even works for Raspberry Pi
  • Awesome-Selfhosted: has many free web services packages

Phone (Android only)

  • De-google your phone with microG Project
  • Play store: F-droid (Bonus: many open source apps that are paid apps on Google store offer the full version for free on F-droid to encourage you to move away from Google Play), Yalp Store

Research

  • restoreprivacy.com
  • Rob Braxman Tech (He knows about the nasty dictators like the Chinese Communist Party. Don’t think you are safe in America. The reach of the Chinese Communist Party Mafia, formerly known as the Chinese SOVIET Republic) is beyond our imagination.

Alternatives to Big Tech respecting privacy (for now)

  • Search (Google): DuckDuckGo
  • Browser (Chrome): Brave
  • Email (Gmail): see above (self-host) or ProtonMail (zero knowledge encryption)
  • Cloud (Google Drive, OneDrive, Dropbox, etc): see above (self-host) or use zero-knowledge encryption
  • Text/Chat (Whatsapp, Line): Signal App
  • Calling: Telegram has better voice quality than signal, but sometimes it has weird behavior on certain phones. Telegram does not have zero-knowledge proof, so it’s up to Pavel Durov (he’s usually good at not bending to totalitarians).

Alternatives to Big Tech that refuses to censor and manipulate users (for now)

  • Video (Youtube): Odysee (LBRY), Rumble
  • Facebook: MeWe
  • Twitter: Gab, Safechat, CloutHub has a crappy search feature, Parler now has PC bots patrolling and misfiring

Zero-knowledge encryption means the server have no access to the info you put in there as they are all encrypted and protected by a password which only you have (preferably use zero-knowledge proof so the owner of the server do not have any master keys to see your data: you lost the key and the data is practically gone forever)

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