In this tutorial, How to Configure " Postfix only allow whitelisted Recipient Domain ". We test environment with user data. To minimize the risk of sending to unwanted email recipients. Step 1: Add line into main.cf file as below smtpd_recipient_restrictions = check_recipient_access hash:/etc/postfix/recipient_domains, reject Note: Warring /etc/postfix/recipient_domains, reject , Allow receive email in recipient_domain, and REJECT All domain not in whitelisted domain. Step 2: To create recipient domain is the whitelist file mycompany.com OK mail.huuphan.com OK Note: only two domain mycompany.com and mail.huuphan.com receive mail Step 3: To generate hash file: $ sudo postmap /etc/postfix/recipient_domains Step 4: To restart postfix service $ sudo /etc/init.d/postfix restart Now to try sending an email to a another domain not in whitelist. You will find error something like that as below: NOQUEUE: reject: RCPT from …: 554 5.7.1 <[email protected]&g

In this tutorial, how to change string content of file as arguments. I written  Bash script arguments from a file content as below: Input file How to change NAME and DOMAIN in input file with any arguments in content as below. My name: NAME My Blog: https:// DOMAIN .com Output file with arguments default value My name: Huu My Blog: https://huuphan.com Output file with arguments another vaule  My name: Devops My Blog: https://devopsroles.com My bash script  $ cat arguments_file.sh The content bash script #!/bin/bash argument1=Huu argument2=huuphan INPUT=/home/huupv/scripts/input.txt OUTPUT=/home/huupv/scripts/output.txt RED='\033[0;31m' NC='\033[0m' # No Color if [ $# -eq 2 ];then     argument1=$1     argument2=$2 fi sed -f - "$INPUT" > "$OUTPUT"<<EOF     s/NAME/$argument1/g     s/DOMAIN/$argument2/g EOF Running bash script with default value $ ./arguments_file.sh The output as picture below: To run

In this tutorial, I have written bash script Bash script argument default value and takes optional input arguments. Using $# argument to input parameter  in bash script. To run bash script with argument default ./def_argument_default.sh The display argument default as below: Running bash script with argument   ./def_argument_default.sh argument1 argument2 argument3 The display bash script with argument as below: My bash script argument default value and takes optional input arguments as below: #!/bin/bash ############### # bash script argument default value # running argument default:  #    ./def_argument_default.sh  # Running optional input argument: #    ./def_argument_default.sh argument1 argument2 argument3 # ############### argument1=HUU argument2=PHAN argument3=www.huuphan.com RED='\033[0;31m' NC='\033[0m' # No Color if [ $# -eq 3 ];then     argument1=$1     argument2=$2     argument3=$3 fi echo -e "First Name: $RED \t$

NGINX Solution for Apache ProxyPassReverse Apache configure <VirtualHost myhost:8888>     ServerName myhost     DocumentRoot /path/to/myapp/public     ProxyPass / http://myapp:8080/     ProxyPassReverse / http://myapp:8080/ </VirtualHost> Nginx Reverse Proxy Configure Nginx not have ProxyPassReverse. Therefore a few missing HTTP header. Solve problem Nginx for Apache ProxyPassReverse as below: server {     listen 80;     server_name  www.huuphan.com;     location /home {     proxy_set_header Host $host;         proxy_pass http://IP_Apache:8888;     }     location /app {     proxy_set_header Host $host;         proxy_set_header X-Forwarded-Host $host:$server_port;         proxy_set_header X-Forwarded-Server $host;         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;         proxy_pass http://IP_TOMCAT:8080;     } }