I bought a Raspberry Pi 4, so I made a note of the setup details. SSH, VNC, UFW, etc.

environment

Physics

--Raspberry Pi 4 Model B / 4GB OK do version --HDMI-> HDMI Micro Conversion Adapter --HDMI monitor --Wired USB keyboard --WiFi router --USB Type C cable and its power supply --Android smartphone (Huawei P30 Pro) --SanDisk microSD

logic

Raspbian GNU/Linux 10 (buster)
RLogin 2.24.9
JuiceSSH

What i did

Get OS

Drop Raspbian Buster with desktop and recommended software from raspberrypi.org and unzip it.
Drop balena Etcher from balena.io and install it
Burn the unzipped .img to microSD with balena Etcher
Insert the microSD into the Raspberry Pi

Rasppie setup

Connect the monitor, keyboard, and powered USB-C cable to the Raspberry Pi
Wait a few minutes and the setup wizard will appear, so proceed appropriately.
Set to connect to the WiFi router on the way
After completing the setup wizard, open the menu with WinKey and enable SSH and VNC in Settings> Raspberry Pi Settings.
Shut down
Unplug everything except the power USB

RDP settings

SSH to Raspberry Pi sudo apt-get update
When you're done, sudo apt-get install xrdp
Confirm connection from Windows 10 Remote Desktop Connection

SSHD settings

Change the standby port and change the authentication method

Change the standby port and external connection

sudo nano /etc/ssh/sshd_config
Change Port 22 to a suitable port

Change of authentication method

Generate an authentication key with the RLogin function
Change to the following settings in sudo nano / etc / ssh / sshd_config

PubkeyAuthentication yes
AuthorizedKeysFile      .ssh/authorized_keys .ssh/authorized_keys2
PasswordAuthentication no
PermitEmptyPasswords no

Create ~ / .ssh / authorized_keys
Copy the public key and paste it into the first line of ~ / .ssh / authorized_keys
Restart SSHD with sudo /etc/init.d/ssh restart
OK if you can reconnect from RLogin

SSH connection from Android

Spit the private key from RLogin
Read the private key with Juice SSH
End

Installing and configuring Uncomplicated Firewall

sudo apt install ufw
systemctl start ufw
Enable Firewall with sudo ufw enable
Make a hole in SSH
sudo ufw allow SSH port number
Make a hole in VNS
Connect to Raspberry Pi from Windows RDP
You will be kicked, so look at the log at cat /var/log/ufw.log
The DPT being kicked was 3389, so sudo ufw allow 3389
According to help.ubuntu.com, SPT is the Source Port and DPT is the Destination Port.
Check the settings with sudo ufw status numbered
Check SSH and RDP connection

Raspberry Pi 4 setup memo