Important After many years of service, the PC Engines APU platform is now EOL.
This guide demonstrates how to build a wired/wireless router using the PC Engines APU platform and a free operating system like OpenBSD or Debian to be used for network address translation, as a stateful firewall, to filter Web traffic, and more.
I am not responsible for anything you do by following any part of this guide!
The completed router configuration will enable:
- An egress Ethernet interface for Internet routing - can be connected to WAN or a cable modem
- A local wireless interface on
192.168.1.0/24
- A local Ethernet interface on
172.16.1.0/24
- A local Ethernet interface on
10.8.1.0/24
- An additional (4th) Ethernet interface is available on APU4
This guide should work on any PC Engines APU model. Here is a suggested parts list:
Part | Description | Cost |
---|---|---|
apu4c4 | apu4c4 system board | $117.50 |
case1d2bluu | Enclosure 3 LAN, blue | $9.40 |
ac12vus2 | AC adapter 12V 2A US plug | $4.10 |
msata16g | SSD M-Sata 16GB MLC, Phison S11 | $15.50 |
wle200nx | Compex WLE200NX miniPCI express card | $19.00 |
2 x pigsma | Cable I-PEX -> reverse SMA | $2.70 |
2 x antsmadb | Antenna reverse SMA dual band | $4.10 |
Note WLE600VX and WLE900VX cards will likely not work due to regulatory compliance reasons.
To connect over serial, you will need a USB to Serial (9-Pin) Converter Cable and Modem Serial RS232 Cable, also available from PC Engines.
See Issue #1 for a list of alternative parts.
Clear an area to work and unpack all the materials. Follow the apu cooling assembly instructions to install the heat conduction plate.
Attach the mSATA disk and miniPCI wireless adapter in their respective slots.
See the relevant APU series manual for detailed board information:
Note Wireless radio cards are ESD sensitive, especially the RF switch and the power amplifier. To avoid damage by electrostatic discharge, the following installation procedure is recommended:
- Touch your hands and the bag containing the radio card to a ground point on the router board (for example one of the mounting holes). This will equalize the potential of radio card and router board.
- Install the radio card in the miniPCI express socket.
- Install the pigtail cable in the cut-out of the enclosure. This will ground the pigtail to the enclosure.
- Touch the I-PEX connector of the pigtail to the mounting hole to discharge, then plug onto the radio card.
To avoid arcing, plug in the DC jack first, then plug the power adapter into mains.
Press F10
during boot and select Payload [memtest]
to complete at least one pass.
The APU serial connection uses 115200 baud rate, 8N1 (8 data bits, no parity, 1 stop bit).
On OpenBSD, use cu:
doas cu -r -s 115200 -l cuaU0
On Linux, use screen:
screen /dev/ttyUSB0 115200 8N1
Or use minicom:
sudo minicom -D /dev/ttyUSB0
Power on the APU and make note of the firmware version displayed briefly during boot.
Check for the latest PC Engines firmware version at pcengines.github.io
Note As of 2023, PC Engines firmware is no longer being updated - see announcement
To update firmware, first download and extract TinyCore Linux.
Download and import the firmware signing key, then check the file signature:
$ curl -LO https://raw.githubusercontent.com/3mdeb/3mdeb-secpack/master/customer-keys/pcengines/release-keys/pcengines-open-source-firmware-release-4.19-key.asc
$ gpg --import pcengines-open-source-firmware-release-4.19-key.asc
gpg: key 0x30A53DE2F5A6D89A: 1 signature not checked due to a missing key
gpg: key 0x30A53DE2F5A6D89A: public key "PC Engines open-source firmware release 4.19 signing key" imported
gpg: Total number processed: 1
gpg: imported: 1
$ gpg apu4_v4.19.0.1.SHA256.sig
gpg: assuming signed data in 'apu4_v4.19.0.1.SHA256'
gpg: Signature made Thu 02 Feb 2023 03:22:57 AM PST
gpg: using RSA key 05CF36F166C3D676A08AB70F30A53DE2F5A6D89A
gpg: Good signature from "PC Engines open-source firmware release 4.19 signing key" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 05CF 36F1 66C3 D676 A08A B70F 30A5 3DE2 F5A6 D89A
$ shasum -a 256 apu4_v4.19.0.1.rom 2>/dev/null | grep -q $(cat apu4_v4.19.0.1.SHA256 | awk '{print $1}') && echo ok
ok
Mount a USB disk and write the TinyCore image, copy the .rom
file:
curl -O https://pcengines.ch/file/apu2-tinycore6.4.img.gz
gzip -d apu2-tinycore6.4.img.gz
sha256sum apu2-tinycore6.4.img
f5a20eeb01dfea438836e48cb15a18c5780194fed6bf21564fc7c894a1ac06d7 apu2-tinycore6.4.img
sudo dd if=apu2-tinycore6.4.img of=/dev/sdd bs=1M
sudo mkdir /mnt/usb
sudo mount /dev/sdd1 /mnt/usb
sudo cp -v apu4_*.rom /mnt/usb
sudo umount /mnt/usb
Connect the USB disk to the APU, press F10
at boot and select the USB disk:
SeaBIOS (version rel-1.14.0.1-0-g8610266a)
Press F10 key now for boot menu
Select boot device:
1. USB MSC Drive Samsung Flash Drive DUO 1100
2. AHCI/0: SB2 ATA-11 Hard-Disk (111 GiBytes)
3. Payload [setup]
4. Payload [memtest]
Check the current version:
root@pcengines:~# dmesg | grep apu
[ 0.000000] DMI: PC Engines apu4/apu4, BIOS v4.10.0.1 09/10/2019
Save the existing version and write the new one:
root@pcengines:~# cd /media/SYSLINUX
root@pcengines:/media/SYSLINUX# flashrom -p internal -r apu4.rom.$(dmidecode -s baseboard-serial-number|tail -n1).$(date +%F)
[...]
Found Winbond flash chip "W25Q64.V" (8192 kB, SPI) mapped at physical address 0xff800000.
Reading flash... done.
root@pcengines:/media/SYSLINUX# flashrom -p internal -w apu4_v4.19.0.1.rom
[...]
Found Winbond flash chip "W25Q64.V" (8192 kB, SPI) mapped at physical address 0xff800000.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... VERIFIED.
Unplug the USB disk and reboot
Optional On reboot, select F10
and Payload [setup]
then w
to enable BIOS write protection then s
to save and reboot.
Verify the version by checking serial output during boot:
PC Engines apu4
coreboot build 20230131
BIOS version v4.19.0.1
From OpenBSD:
$ dmesg | grep bios
bios0 at mainbus0: SMBIOS rev. 2.8 @ 0xcfe8b020 (13 entries)
bios0: vendor coreboot version "v4.19.0.1" date 01/31/2023
bios0: PC Engines apu4
acpi0 at bios0: ACPI 6.0
From Debian:
$ sudo dmesg | grep apu
[ 0.000000] DMI: PC Engines apu4/apu4, BIOS v4.19.0.1 01/31/2023
Note APU firmware can also be updated from Debian, without rebooting to TinyCore Linux:
sudo apt install flashrom
wget https://3mdeb.com/open-source-firmware/pcengines/apu4/apu4_v4.19.0.1.rom
sudo flashrom -p internal -w apu2_v4.19.0.1.rom
To complete the update, shut down Debian and power off the APU fully, then reboot.
Use another computer to prepare an installer for either OpenBSD or Debian.
Download the installation image - amd64/install75.img
- as well as SHA256
and SHA256.sig
files.
Verify the signatures file and hash of the installation image:
cat /etc/signify/openbsd-75-base.pub
untrusted comment: openbsd 7.5 base public key
RWRGj1pRpprAfgeF/rgld4ubduChLvTkigA1Zj7WLDsVA4qfYSWOEI8q
signify -C -p /etc/signify/openbsd-75-base.pub -x SHA256.sig install75.img
Signature Verified
install75.img: OK
Insert a USB disk. Run dmesg
to identify its label. Then copy the installation file to the USB disk:
On OpenBSD:
doas dd if=install75.img of=/dev/rsd2c bs=1m
On Linux:
sudo dd if=install75.img of=/dev/sdd bs=1M
Download the latest network installation image - as well as SHA512SUMS
and SHA512SUMS.sign
files.
Verify the signatures file and hash of the installation image:
$ gpg SHA512SUMS.sign
gpg: assuming signed data in 'SHA512SUMS'
gpg: Signature made Sat 07 Oct 2023 01:24:41 PM PDT
gpg: using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Can't check signature: No public key
$ gpg --keyserver hkps:https://keyserver.ubuntu.com:443 --recv DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: key 0xDA87E80D6294BE9B: public key "Debian CD signing key <[email protected]>" imported
gpg: Total number processed: 1
gpg: imported: 1
$ gpg SHA512SUMS.sign
gpg: Signature made Sat 29 Jun 2024 01:50:21 PM PDT
gpg: using RSA key DF9B9C49EAA9298432589D76DA87E80D6294BE9B
gpg: Good signature from "Debian CD signing key <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258 9D76 DA87 E80D 6294 BE9B
OpenBSD:
grep $(sha512 -q debian-12.6.0-amd64-netinst.iso) SHA512SUMS
712cf43c5c9d60dbd5190144373c18b910c89051193c47534a68b0cd137c99bd8274902f59b25aba3b6ba3e5bca51d7c433c06522f40adb93aacc5e21acf57eb debian-12.6.0-amd64-netinst.iso
Linux:
grep $(sha512sum debian-12.6.0-amd64-netinst.iso) SHA512SUMS
SHA512SUMS:712cf43c5c9d60dbd5190144373c18b910c89051193c47534a68b0cd137c99bd8274902f59b25aba3b6ba3e5bca51d7c433c06522f40adb93aacc5e21acf57eb debian-12.6.0-amd64-netinst.iso
Insert a USB disk. Run dmesg
to identify its label. Then copy the installation file to the USB disk.
OpenBSD:
doas dd if=debian-12.6.0-amd64-netinst.iso of=/dev/rsd2c bs=1m
Linux:
sudo dd if=debian-12.6.0-amd64-netinst.iso of=/dev/sdd bs=1M
Unplug the USB disk and plug it into the APU.
Press F10
at boot and select the USB disk.
Set the serial console parameters:
Booting from Hard Disk...
Using drive 0, partition 3.
Loading......
probing: pc0 com0 com1 mem[639K 3325M 752M a20=on]
disk: hd0+ hd1+
>> OpenBSD/amd64 BOOT 3.47
boot> stty com0 115200
boot> set tty com0
switching console to com>> OpenBSD/amd64 BOOT 3.47
boot> [Press Enter]
Select the Install option:
Welcome to the OpenBSD/amd64 7.5 installation program.
(I)nstall, (U)pgrade, (A)utoinstall or (S)hell? I
When presented with a list of network interfaces, em0
is the Ethernet port closest to the serial port:
Available network interfaces are: em0 em1 em2 em3 vlan0.
Use DHCP or configure a static route:
Network interface to configure? (name, lladdr, '?', or 'done') [done] em0
IPv4 address for em0? (or 'autoconf' or 'none') [autoconf] 192.168.1.2
Netmask for em0? [255.255.255.0]
IPv6 address for em0? (or 'autoconf' or 'none') [none]
Available network interfaces are: em0 em1 em2 em3 vlan0.
Network interface to configure? (name, lladdr, '?', or 'done') [done]
Default IPv4 route? (IPv4 address or 'none') 192.168.1.1
add net default: gateway 192.168.1.1
DNS domain name? (e.g. 'example.com') [my.domain] local
DNS nameservers? (IP address list or 'none') [none] 192.168.1.1
Configure the root password and set up a user account:
Password for root account? (will not echo)
Password for root account? (again)
Start sshd(8) by default? [yes]
Change the default console to com0? [yes]
Available speeds are: 9600 19200 38400 57600 115200.
Which speed should com0 use? (or 'done') [115200]
Setup a user? (enter a lower-case loginname, or 'no') [no] sysadm
Full name for user sysadm? [sysadm]
Password for user sysadm? (will not echo)
Password for user sysadm? (again)
Select the internal mSATA disk and default options for partitioning:
Available disks are: sd0 sd1.
Which disk is the root disk? ('?' for details) [sd0] ?
sd0: ATA, SB2, SBFM naa.0000000000000000 (119.2G)
sd1: PNY, USB 2.0 FD, 1100 serial.00000000000000000000 (29.9G)
Available disks are: sd0 sd1.
Which disk is the root disk? ('?' for details) [sd0]
Note The "unused" partition (/dev/sd0c
) is actually the entire disk.
Select a mirror and start the installation:
HTTP Server? (hostname, list#, 'done' or '?') cdn.openbsd.org
Server directory? [pub/OpenBSD/7.5/amd64]
Select sets by entering a set name, a file name pattern or 'all'. De-select
sets by prepending a '-', e.g.: '-game*'. Selected sets are labelled '[X]'.
[X] bsd [X] base75.tgz [X] game75.tgz [X] xfont75.tgz
[X] bsd.mp [X] comp75.tgz [X] xbase75.tgz [X] xserv75.tgz
[X] bsd.rd [X] man75.tgz [X] xshare75.tgz
Set name(s)? (or 'abort' or 'done') [done]
After installation is complete, unplug the USB disk and reboot. See the OpenBSD FAQ for more information.
At the install menu, select Tab
to edit boot options and replace quiet
with:
console=ttyS0,115200n8
Select Enter
and select an available resolution:
Undefined video mode number: 314
Press <ENTER> to see video modes available, <SPACE> to continue, or wait 30 sec
Mode: Resolution: Type:
0 F00 80x25 CGA/MDA/HGC
Enter a video mode or "scan" to scan for additional modes: 0
Configure a network adapter - enp1s0
is the interface closest to the serial port.
Select Guided - use entire disk and set up LVM
as the partition method. Be sure to select internal mSATA drive and not the USB disk as the installation target (usually sda
).
Select Separate /home, /var, and /tmp partitions
as the partitioning scheme.
During Software selection
- de-select everything except SSH server.
Select the internal mSATA drive and not the USB disk as the GRUB loader target.
The following boot parameters have been appended to /etc/boot.conf
by the installer and everything should just work:
stty com0 115200
set tty com0
After the GRUB menu, output may get stuck at:
Loading Linux 6.1.0-23-amd64 ...
Loading initial ramdisk ...
If so, reboot and press e
at the GRUB menu to enter edit mode, scroll down and replace the word quiet
with:
console=ttyS0,115200n8
Note If arrow keys do not work in GRUB, try using Emacs key bindings to navigate the text field:
Control-B
to move leftControl-F
to move rightControl-P
to move upControl-N
to move down
Press Control-X
to continue booting and you should see console output.
Note If you get an error like, Alert! /dev/sdX1 does not exist dropping to shell
and are dropped to an initramfs prompt, reboot and edit the quiet
line to point to /dev/sda1
or correct partition.
Log in as root
and install pending updates or switch to -current:
syspatch
Install any pending firmware updates:
fw_update
Edit /etc/doas.conf
to allow the regular user to run privileged commands without a password:
permit nopass keepenv :wheel
permit nopass keepenv root
Install any needed software:
pkg_add bash zsh vim curl free pftop vnstat
Reboot to complete any pending updates.
Log in as root
to get started.
If necessary, update GRUB by editing /etc/default/grub
and removing or replacing quiet
with console=ttyS0,115200n8
then update the configuration:
update-grub
Install any pending updates and necessary software:
apt update && apt -y upgrade
apt -y install lshw lsof vim zsh git sudo dnsmasq net-tools iptables tcpdump hostapd firmware-atheros
Optional Change the default login shell to zsh for the primary user:
chsh -s /usr/bin/zsh sysadm
On the APU, set a local network interface address and make it permanent:
doas ifconfig em1 10.8.1.1 255.255.255.0
echo "inet 10.8.1.1 255.255.255.0" | doas tee /etc/hostname.em1
Configure an OpenBSD client with DHCP by following the Networking FAQ or using a static address:
doas ifconfig em1 10.8.1.4 255.255.255.0
ping -c 1 10.8.1.1
PING 10.8.1.1 (10.8.1.1): 56 data bytes
64 bytes from 10.8.1.1: icmp_seq=0 ttl=255 time=0.845 ms
Optional Randomize MAC addresses on boot:
echo "lladdr random" | doas tee -a /etc/hostname.em0 /etc/hostname.em1 /etc/hostname.em2
On the APU and on another computer, determine the interface names available:
lshw -C network | grep "logical name"
On the APU, edit /etc/network/interfaces
to append:
auto enp2s0
iface enp2s0 inet static
address 10.8.1.1
netmask 255.255.255.0
gateway 10.8.1.1
Where enp2s0
is the network interface one port away from the serial port.
Restart networking and bring up the interface:
service networking restart
ifup enp2s0
On another Linux computer, edit /etc/network/interfaces
to append:
auto eno1
iface eno1 inet static
address 10.8.1.2
netmask 255.255.255.0
gateway 10.8.1.1
Then also restart networking and bring up the interface:
sudo service networking restart
sudo ifup eno1
Or on another OpenBSD computer, edit /etc/hostname.em0
to append:
inet 10.8.1.4 255.255.255.0
It should now be possible to ping the router:
ping -c 1 10.8.1.1
PING 10.8.1.1 (10.8.1.1): 56 data bytes
64 bytes from 10.8.1.1: icmp_seq=0 ttl=64 time=0.519 ms
To configure the wireless interface, edit /etc/network/interfaces
on the APU to include:
auto wlp5s0
iface wlp5s0 inet static
address 192.168.1.1
netmask 255.255.255.0
hostapd /etc/hostapd.conf
Reboot after verifying network connectivity.
From a client, an SSH connection to the APU should be possible, but not yet authorized:
$ ssh [email protected]
The authenticity of host '10.8.1.1 (10.8.1.1)' can't be established.
ECDSA key fingerprint is SHA256:AAAAA.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '10.8.1.1' (ECDSA) to the list of known hosts.
Permission denied (publickey,password).
If using a YubiKey, copy its public key to clipboard:
ssh-add -L | awk '{print $1" "$2}' | xclip
Or generate a new SSH key on the client and copy it to clipboard:
ssh-keygen -f -C 'sysadm' ~/.ssh/pcengines
xclip ~/.ssh/pcengines.pub
On the APU, over the serial connection, as the primary user (e.g., sysadm
- not root
), configure SSH to accept that key by pasting it into ~/.ssh/authorized_keys
:
mkdir ~/.ssh ; cat > ~/.ssh/authorized_keys
[Paste clipboard contents using the middle mouse button or Shift-Insert]
[Then press Control-D to save]
SSH from a client will now work:
$ ssh [email protected] -i ~/.ssh/pcengines
Host key fingerprint is SHA256:AAAAA
Linux pcengines 4.9.0-8-amd64 #1 SMP Debian 4.9.130-2 (2018-10-27) x86_64
sysadm@pcengines~ %
Configure the connection on a client by editing ~/.ssh/config
:
Host pcengines
HostName 10.8.1.1
IdentityFile ~/.ssh/pcengines
User sysadm
Port 22
ControlMaster auto
ControlPath ~/.ssh/master-%r@%h:%p
ControlPersist 1m
Connect using the new alias:
ssh pcengines
Download configuration files:
git clone https://github.com/drduh/config
The serial connection can now be terminated. Be sure to log out with Ctrl-D
or exit
before disconnecting, otherwise anyone can plug in the serial cable to assume your session without a passphrase.
Dnsmasq will provide DHCP and handle DNS for the local network(s).
Use drduh/config/dnsmasq.conf for a configuration example, including blocked domains:
cp config/dnsmasq.conf /etc/dnsmasq.conf
cat config/domains/* | tee -a /etc/dnsmasq.conf
vim /etc/dnsmasq.conf
Configure additional blocklist:
git clone https://github.com/StevenBlack/hosts
sudo cp hosts/hosts /etc/dns-blocklist
To install dnsmasq as a service enabled on boot:
doas pkg_add dnsmasq
doas rcctl start dnsmasq
doas rcctl enable dnsmasq
Note Wireless performance is currently significantly worse on OpenBSD than Debian.
Edit /etc/hostname.athn0
to include:
inet 192.168.1.1 255.255.255.0
media autoselect mode 11n mediaopt hostap chan 11
nwid NAME wpakey "PASSWORD"
Restart networking:
doas sh /etc/netstart
Install the default hostapd configuration:
cat /usr/share/doc/hostapd/examples/hostapd.conf | sudo tee -a /etc/hostapd.conf
Or use drduh/config/hostapd.conf:
sudo cp config/hostapd.conf /etc/hostapd.conf
Edit the configuration to set the network name and password.
Tip Avoid passwords with the characters '
and "
.
sudo vim /etc/hostapd.conf
Ensure hostapd starts:
sudo hostapd /etc/hostapd.conf
Note You may need to manually assign the interface an address:
sudo ifconfig wlp5s0 192.168.1.1
In order to be a router, IP forwarding must be enabled.
Enable now and on boot:
doas sysctl net.inet.ip.forwarding=1
echo "net.inet.ip.forwarding=1" | doas tee -a /etc/sysctl.conf
Enable now and on boot:
sudo sysctl -w net.ipv4.ip_forward=1
echo "net.ipv4.ip_forward=1" | sudo tee --append /etc/sysctl.conf
See PF - Building a Router, or use drduh/config/pf files:
doas mkdir /etc/pf
doas cp config/pf/pf.conf /etc/
doas cp config/pf/blocklist config/pf/martians config/pf/private /etc/pf/
Turn PF off and back on again:
doas pfctl -d
doas pfctl -e -f /etc/pf.conf
Optional Use drduh/config/scripts/pf-blocklist.sh to find and block unwanted networks.
To inspect blocked traffic:
doas tcpdump -ni pflog0
Use Iptables to manage a stateful firewall.
Use drduh/config/scripts/iptables.sh and edit it to your needs:
sudo cp config/scripts/iptables.sh /etc
sudo vim /etc/iptables.sh
sudo chmod +x /etc/iptables.sh
sudo /etc/iptables.sh
Save the firewall rules to apply them on boot:
sudo iptables-save | tee /etc/iptables/rules.v4
Privoxy is a powerful Web proxy capable of filtering and rewriting URLs to block ads, upgrade HTTP connections, and more.
Install Privoxy:
sudo apt -y install privoxy
Use drduh/config/privoxy/config and drduh/config/privoxy/user.action - or edit the configuration yourself.
sudo cp config/privoxy/config config/privoxy/user.action /etc/privoxy/
Restart the service and check the log:
sudo service privoxy restart
sudo tail -f /var/log/privoxy/logfile
Lighttpd with mod_magnet makes for a highly capable Web server which can be used to replace ad images with custom content, upload and share content on the local network, act as a captive portal, and more.
Install Lighttpd with ModMagnet:
sudo apt -y install lighttpd lighttpd-mod-magnet
Use drduh/config/lighttpd/lighttpd.conf and drduh/config/lighttpd/magnet.luau - or edit the configuration yourself.
sudo cp config/lighttpd/lighttpd.conf config/lighttpd/magnet.luau /etc/lighttpd/
Restart the service and check the log:
sudo service lighttpd restart
sudo cat /var/log/lighttpd/error.log
First install minisign
or build from source
Download the latest Linux release - dnscrypt-proxy-linux_x86_64-*.tar.gz
, verify it and edit the configuration:
curl -LfO https://github.com/DNSCrypt/dnscrypt-proxy/releases/download/2.1.5/dnscrypt-proxy-linux_x86_64-2.1.5.tar.gz
curl -LfO https://github.com/DNSCrypt/dnscrypt-proxy/releases/download/2.1.5/dnscrypt-proxy-linux_x86_64-2.1.5.tar.gz.minisig
minisign -Vm dnscrypt-proxy-*.tar.gz -P RWTk1xXqcTODeYttYMCMLo0YJHaFEHn7a3akqHlb/7QvIQXHVPxKbjB5
Signature and comment signature verified
Trusted comment: timestamp:1691773871 file:dnscrypt-proxy-linux_x86_64-2.1.5.tar.gz hashed
tar xf dnscrypt-proxy*.gz
cp config/dnscrypt-proxy.toml linux-x86_64/
cd linux-x86_64/
vim dnscrypt-proxy.toml
Optional Download and configure a hosts blacklist:
git clone https://github.com/DNSCrypt/dnscrypt-proxy
cd dnscrypt-proxy/utils/generate-domains-blocklists
python3 generate-domains-blocklist.py > blocklist-$(date +%F).txt
cp blocklist-$(date +%F).txt ~/linux-x86_64/blocklist.txt
Start the program and check dnscrypt.log
for success or errors:
sudo ./dnscrypt-proxy
Once everything is working as expected, install and start dnscrypt-proxy as a service:
sudo ./dnscrypt-proxy -service install
sudo ./dnscrypt-proxy -service start
tail -f dnscrypt.log
To confirm the firewall is configured correctly, run port scans from an internal and external hosts, for example:
nmap -v -A -T4 192.168.1.1 -Pn
To view blocked packets, tail the system message buffer on Linux:
$ sudo dmesg -wH
[Jul 1 12:00] DROPIN>IN=enp1s0 OUT= MAC=00:00:00:00:00:00:00:00:00:00:00:00:00:00 SRC=192.168.1.10 DST=192.168.1.1 LEN=64 TOS=0x00 PREC=0x00 TTL=64 ID=29501 DF PROTO=TCP SPT=43228 DPT=554 WINDOW=16384 RES=0x00 SYN URGP=0
[...]
On OpenBSD, blocked packets will be sent to the PF log interface:
$ doas tcpdump -ni pflog0
tcpdump: listening on pflog0, link-type PFLOG
12:00:00.000000 192.168.1.10.40770 > 192.168.1.1.1720: S 3331100898:3331180098(0) win 29200 <mss 1460,sackOK,timestamp 232580000 0,nop,wscale 7> (DF)
[...]
Install a USB camera and configure Motion to detect and monitor physical access.
(Linux only) Increase system entropy with a hardware device like OneRNG.
Check open network ports with doas fstat | grep net
and doas netstat -a -n -p udp -p tcp
Check running processes and sessions with ps -A
and last
Pay attention to OpenBSD errata and apply security fixes periodically with doas syspatch
OpenBSD releases occur approximately every six months - follow current snapshots for faster updates by periodically running doas sysupgrade -s
to reboot and install updates.
Check temperatures with sysctl hw.sensors
or configure sensorsd.
Check open ports and listening programs with sudo lsof -Pni
and sudo netstat -npl
Check running processes and logged-in users with ps -eax
and last -F
Pay attention to Debian security advisories and run sudo apt update && sudo apt upgrade
periodically or configure unattended upgrades.
Install and enable SELinux:
sudo apt -y install selinux-basics selinux-policy-default
sudo selinux-activate
sudo reboot
Or, install and enable AppArmor, then reboot:
sudo apt -y install apparmor apparmor-profiles apparmor-utils
sudo mkdir -p /etc/default/grub.d
echo 'GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT apparmor=1 security=apparmor"' | sudo tee /etc/default/grub.d/apparmor.cfg
sudo update-grub && sudo reboot
Install and enable Firejail:
sudo apt -y install firejail firejail-profiles
sudo firecfg
See also Debian SSD Optimizations.