JetKVM review

I received a JetKVM last week. Here is my take.

the good,

• the metal casing feels nice
• Web UI is clean, responsive, and intuitive. 

the bad,

• Although it supports IPv6 SLAAC, the IPv6 address is not shown anywhere in the Web UI or on-device screen. I had to enable developer mode and SSH into it to see the address.
• Virtual media does not support loading media from the browser yet.
  
• It uses a mini-HDMI port instead of a regular one.
• Its only USB-C port is for both power and data (HID and storage emulation). So it comes with a special USB-C cable that splits a USB-C port to a data port and a power port.
• It does not support WiFi. Good for security but bad for convenience.
• Its irregular form factor makes it difficult to mount on a rack.

I recommend it at a price of 88 USD. But if you can wait, GL.iNet's GL-RM1 might be a better choice.

Block clients of a specific AP from accessing WAN on OpenWrt 24.10

I wrote a post on blocking clients of AP from Internet access on Mikrotik router a while ago at https://jim-think.blogspot.com/2023/04/block-internet-access-for-iot-devices.html

I have become dissatisfied with MikroTik's WiFi compatibility. So I switched to Openwrt.

Steps

0. opkg install kmod-nft-bridge

1. Add a WiFi interface for restricted devices.

config wifi-iface 'wifinet2'
    option device 'radio1'
    option mode 'ap'
    option ssid '<redacted>'
    option encryption 'psk2+ccmp'
    option key '<redacted>'
    option ocv '0'
    option network 'lan'   // bridged to lan
    option ieee80211w '1'
    option ifname 'no-internet'  // remember this
 

2. Create a file at  /etc/nftables.d/bridge.sh with following contents.

nft add table bridge filter
nft flush table bridge filter
nft add chain bridge filter prerouting { type filter hook prerouting priority dstnat\; }
nft add rule bridge filter prerouting iifname no-internet mark set 0x1984

3. Add firewall rules in /etc/config/firewall

config rule
    option name 'block-no-internet'
    list proto 'all'
    option src 'lan'
    option dest 'wan'
    option target 'REJECT'
    option mark '0x1984'

config include
        option type 'script'
        option path '/etc/nftables.d/bridge.sh'

4. Reboot or run service firewall restart.

5. Run nft list ruleset to verify. 

References

https://wiki.nftables.org/wiki-nftables/index.php/Setting_packet_metainformation#packet_mark

https://openwrt.org/docs/guide-user/firewall/fw3_configurations/bridge 

https://openwrt.org/docs/guide-user/firewall/firewall_configuration#includes_2203_and_later_with_fw4

Viltrox 28mm F4.5 E mount AF lens review

I have been using a Viltrox AF 28mm F4.5 FE on Sony A6400 for a while. Here is my review.

Good,

• extremely thin and lightweight
  
• auto focus
  
• AF motor is quiet
• affordable
• built-in lens cover

Bad,

• Aperture is fixed at f/4.5 which is too wide for landscape.
• No manual focus mode
• No filter attachment threads
• Prominent flare
• AF motor can be heard on video recordings
• No optical stabilization (not unexpected given the price)

Remeber screen brightness in Fedora

My laptop's screen is always at the lowest brightness when resuming from sleep. It is very annoying. I found a fix.

 

Create an executable file at /usr/lib/systemd/system-sleep/brightness with following contents,

#!/usr/bin/sh

case $1 in
    pre) cp /sys/class/backlight/intel_backlight/brightness  /tmp/saved_brightness ;;
    post) cp /tmp/saved_brightness /sys/class/backlight/intel_backlight/brightness  ;;
esac

2022 Civic EX Canadian version review

Good,

• It has heated front seats and heated steering wheel.
• Handling is agile.
• Good fuel efficiency.
• It has remote start without subscriptions.
• The car does not seem to be connected to cellular networks.
• AC control has physical knobs. 
• It prompts me to add windshield washer fluid when the level is low.
  

Bad,

• Lane centering does not work as well as Toyota. It feels jerky.
  
• No wireless phone projection.
• No auto-dimming rear view mirror option.
• No Aux audio input port.
  

Ugly

• Steering wheel controls are complicated. It has toggles, wheels, and buttons.
• Seating position is low. I can see part of the hood even at the highest position.
• Only the two front door windows support one-touch up/down.
• Honda issued a recall for "sticky steering". But all three dealerships nearby ran out of parts and could not repair the recall.
  

Switch Fedora 41 from GRUB2 to systemd-boot

Fedora uses GRUB2 boot loader by default. I want to switch to systemd-boot. Below are the steps. All executed with sudo.

Run ls /sys/firmware/efi to ensure the system was booted in EFI mode. Stop if the path does not exist.

Run bootctl status to confirm that system-boot was not the boot loader.

Run df -h to ensure the EFI system partition's free space is larger then /boot's used space.

dnf install -y systemd-boot

mkdir /efi

nano /etc/fstab
Move the /boot/efi mount point to /efi. Remove the line of /boot.

systemctl daemon-reload

umount /boot/efi

umount /boot

mount /efi

mkdir /efi/$(cat /etc/machine-id)

bootctl install

cat /proc/cmdline | cut -d ' ' -f 2- | tee /etc/kernel/cmdline

nano /etc/kernel/install.conf. Put these two lines
BOOT_ROOT=/efi
layout=bls

kernel-install add $(uname -r) /lib/modules/$(uname -r)/vmlinuz 

dnf reinstall kernel-core 

Reboot. Run bootctl status to confirm that system-boot is the boot loader.

If everything works, delete grub.

rm /etc/dnf/protected.d/{grub,shim}*

dnf remove grubby grub2\* memtest86\* 

 

 

Forward SMS from Android to iPad

The goal is to forward short messages received on a Pixel 4 running Android 12 to an iPadOS 18 device over the Internet.

1. Install Bark on iPad.
   
2. Follow this tutorial to set up a URL like https://api.day.app/<some_random_chars>/. The random chars are the push key.
   
3. Install SMS to URL Forwarder on Android. The app can be downloaded from F-Droid.
4. Add an entry in the SMS to URL forwarder app
5. Set sender to *
   
6. Set webhook URL to https://api.day.app/<some_random_chars>/
7. Set the JSON content to {"title": "%from%", "body": "%text%"}
8. Click test
9. Save the entry if iPad receives a notification.