centos 8 to steam

 sudo dnf update

sudo dnf in centos-release-stream

sudo dnf repolist

sudo dnf distro-sync

cat /etc/centos-release

reboot

dnf yum update

link: https://www.cyberciti.biz/howto/upgrade-migrate-from-centos-8-to-centos-stream-conversion/

centos rdp

for centos 8

sudo dnf groupinstall "Server with GUI"

sudo dnf install epel-release

sudo dnf install xrdp

sudo systemctl enable xrdp --now

sudo systemctl status xrdp

sudo firewall-cmd --add-port=3389/tcp --permanent

sudo firewall-cmd --reload

Change Port: /etc/xrpd/xrdp.ini and restat service

link: https://www.myfreax.com/how-to-install-xrdp-on-centos-8/

Centos not support for update/upgrade

 INFO: Error: Failed to download metadata for repo 'AppStream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

Run:

• sudo sed -i -e "s|mirrorlist=|#mirrorlist=|g" /etc/yum.repos.d/CentOS-*
• sudo sed -i -e "s|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g" /etc/yum.repos.d/CentOS-*
• link: https://www.cnblogs.com/axinno1/p/15884647.html

or

• sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
• sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*
• link: https://www.tecmint.com/error-failed-to-download-metadata-for-repo-appstream/

Fail2Ban With Ubuntu

 Fail2Ban

1. sudo apt install fail2ban -y

2. sudo systemctl status fail2ban.service

3. cd /etc/fail2ban

4. sudo cp jail.conf jail.local

5. sudo nano jail.local

modify bantime, findtime and maxretry

modify enabled = false to true

find [sshd] after add line: enabled = true

find [nginx-http-auth] after add line: enabled = true 

6. sudo systemctl enable fail2ban.service

7. sudo systemctl start fail2ban.service

8. sudo systemctl status fail2ban.service

if u start with error

1. sudo rm jail.local

2. sudo nano jail.local 

[sshd]

enabled  = true

port     = ssh

filter   = sshd

logpath  = /var/log/auth.log

maxretry = 5

findtime = 60m

bantime  = 60m

from: 

https://www.digitalocean.com/community/tutorials/how-to-protect-ssh-with-fail2ban-on-ubuntu-20-04

AWS VPS

Create AWS Account

Getin Free project

https://aws.amazon.com/tw/free/

Choose one of EC2 and Active

1、setting name

2、choose ubuntu

3、Storage can setting 30GB(Max) for free

4、Create certificate*

Active

1、SSH Client

2、use ssh to login and use certificate*

Frist 

1、sudo apt clean

2、sudo apt update -y

3、sudo apt upgrade -y

4、sudo apt-get clean

5、sudo apt-get update -y

6、sudo apt-get upgrade -y

7、sudo apt-get dist-upgrade -y

8、sudo apt-get autoremove -y

Install Editor

1、sudo apt-get install nano -y

Comfirm Version

lsb_release -a

iRedMail White List

• Postfix
  nano /etc/postfix/helo_access.pcre
  Add below:
  /\.domain\.com$/ OK
  /\.domain\.com\.tw$/ OK
• iRedApd
  goto /opt/iredapd/tools
  run below:
  python wblist_admin.py --add --whitelist IP @domain.com @.domain.com user@domain.com
• fail2ban
  nano /etc/fail2ban/jail.local
  add IPs after  ignoreip = IP1 IP2 IP/8 IP/16 IP/24 IP/32