Introduction Encountering the Zimbra error "421 4.7.0 GSmtp" can disrupt your email communication and cause frustration. This error typically indicates issues related to Gmail's SMTP server, which can affect the delivery of emails sent from your Zimbra server.  In this article, we will delve into the causes of the "421 4.7.0 GSmtp" error and provide step-by-step solutions to help you resolve it, ensuring smooth and uninterrupted email communication. zimbra code error 421-4.7.0 This message does not have authentication information or fails to pass 421-4.7.0 authentication checks Gmail SMTP Error Codes Jun 22 11:17:56 mta postfix/smtp[16523]: B67511C61EE: host gmail-smtp-in.l.google.com[74.125.23.27] said: 421-4.7.0 This message does not have authentication information or fails to pass 421-4.7.0 authentication checks. To best protect our users from spam, the 421-4.7.0 message has been blocked. Please visit 421-4.7.0  https://support.google.com/mail/answer/81126#...

Introduction Discover how to use Bash scripts to align output with the  printf  command. Learn various methods for aligning output in Bash scripts, including practical examples and best practices. In Bash scripting, aligning output is a crucial aspect of creating readable and professional scripts. This guide will walk you through using the printf command to format strings and align output effectively. We'll also explore other methods for output alignment in Bash scripts. Using printf to Align Output The printf command in Bash is a versatile tool that allows you to format and align output precisely. Unlike echo , which simply prints text, printf provides control over the format, making it ideal for aligning columns and creating structured output. Basic Syntax: Copy code printf FORMAT [ARGUMENT]... Format Specifiers: %s - String %d - Decimal integer %f - Floating-point number Example: Copy code printf "%-20s %-10s\n" "Name" "Status" printf ...

Introduction Learn how to effectively use IFS (Internal Field Separator) in Bash scripts, particularly within for loops. This comprehensive guide covers basic to advanced examples to enhance your scripting skills. In Bash scripting, mastering the Internal Field Separator (IFS) is key to handling strings and data processing effectively. The IFS variable allows you to control how the shell interprets and splits strings into words, which is particularly useful when iterating over data with for loops. This article explores the meaning and application of IFS in Bash , focusing on its use in for loops with practical examples. What is IFS in Bash? What Does IFS Mean? IFS stands for Internal Field Separator. It is a special shell variable used to determine how Bash splits a string into words. By default, IFS includes space, tab, and newline characters, but you can customize it to suit your needs. Why is IFS Important? Understanding and using IFS allows you to handle and process strings more fl...

Introduction This script is designed to list all IP addresses connected to your server, retrieve geographical information for each IP using ipinfo.io , and display the results in a clean format. This guide will walk you through the script, explaining each part in detail, and ensuring you understand how to implement and use it effectively. What is Bash? Bash (Bourne Again Shell) is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. It has since become the default login shell for most Linux distributions. Bash can execute commands, read and execute commands from a file, and provide constructs for condition testing, looping, and functions. Prerequisites A Linux -based server with administrative privileges. Internet connection for accessing ipinfo.io . Basic knowledge of Bash scripting. List all IP addresses connected to Server us Bash Script Running to bash script list all IP addresses connected to Server ./stu...

Introduction Learn how to check files and directories using a bash script with a step-by-step guide. This tutorial covers basic to advanced techniques to automate file system tasks effectively. Bash scripting is an essential skill for managing files and directories in Unix-like operating systems. This guide will help you create a bash script to check all files and directories in a specific folder. We will walk through the process step-by-step, ensuring that you can easily adapt the script to your needs. Basics of Bash Scripting Before diving into the script, let's briefly cover some bash scripting basics: Shebang ( #!/bin/bash ) : Indicates that the script should be executed using the bash shell. Variables : Store data values. Conditional Statements ( if , else , elif ) : Execute different commands based on conditions. Loops ( for , while ) : Repeat commands for a set of items. Creating the Script To start, create a new bash script file and add the shebang line. Example: Starting ...

Monitoring user activity in your Zimbra email system is crucial for maintaining security and efficiency. Identifying accounts that have not logged in for an extended period can help administrators clean up inactive accounts, enhance system performance, and reduce potential security risks. In this article, we'll guide you through the process of listing Zimbra accounts that have not logged in recently, providing a practical approach to managing and securing your email system. Introduction Monitoring user activity in your Zimbra email system is crucial for maintaining security and efficiency. Identifying accounts that have not logged in for an extended period can help administrators clean up inactive accounts, enhance system performance, and reduce potential security risks.  In this article, we will show you how to list Zimbra accounts that have not logged in recently, providing you with a practical approach to managing and securing your email system. We will guide you through the st...

Many methods to reset root password centos 7. if GRUB 2 bootloader then no longer using in single-user mode as well as emergency mode. To below step by step to reset root password centos 7. You may reading link below : awk useful commands examples CentOS/RHEL Use yum Command To Downgrade Upgrade or Rollback Updates Generate and Verify Files with MD5 Checksum in Linux use inotify-tools on centos Step 1: Start the system, on Grub 2 boot screen, you press the e key as shown below. Step 2: In linux16 line or linuxefi on UEFI system, add parameters end line as shown below. rw init=/bin/bash Using Ctrl+A press or Ctrl+E press to start or end a line. Disable paramenters the rhgb and quiet in order to enable system message as shown top. Step 3: you press Ctrl+x to start single user mode passwd Step 4: update selinux information touch /.autorelabel Step 5: To resume the initialization and finish the system boot. exec /sbin/init Video how to reset root password on cen...

Introduction Setting strong password policies in Zimbra is essential for enhancing the security of your email system. By enforcing robust password requirements, you can protect user accounts from unauthorized access and potential security breaches. In this article, we will guide you through the process of configuring password policies in Zimbra, helping you to implement best practices for password security and safeguard your organization's email communications. How to setting password policies in zimbra? To help your system increase security, password strongest. Setting password policies in Zimbra To get all COS use zmprov command su - zimbra zmprov gac -v | grep Password | sort | uniq To display all attributes as below zimbraFeatureChangePasswordEnabled: TRUE zimbraMobilePolicyAllowSimpleDevicePassword: FALSE zimbraMobilePolicyAlphanumericDevicePasswordRequired: FALSE zimbraMobilePolicyDevicePasswordEnabled: TRUE zimbraMobilePolicyDevicePasswordExpiration: 0 zimbraMobile...

Introduction Backing up and restoring your Zimbra email system is essential for ensuring data security and continuity. Regular backups protect your organization from data loss due to hardware failures, software issues, or other unforeseen events. In this article, we will guide you through the process of backing up and restoring Zimbra, providing you with the necessary steps to safeguard your email data and ensure seamless recovery when needed. In this tutorial, How to " Backup and restore for zimbra mailbox ". How to backup mailbox for accounts? How to restore mailbox for accounts? Backup and restore for zimbra mailbox The format list_account file as below: huupv1@huuphan.com huupv2@huuphan.com The script backup mailbox for all accounts #!/bin/bash FILE= /tmp/list_account DATE=$(date +"%a") ZMBOX=/opt/zimbra/bin/zmmailbox while read account do      echo "---Generating files from backup $account ---"      $ZMBOX -z -m $account -t...

inotifywait - wait for changes to files using inotify. When it comes to real-time monitoring of file system events, inotify-tools is an indispensable tool. Especially for CentOS users, mastering inotify-tools can significantly enhance the efficiency of system administration tasks. This guide will walk you through everything you need to know about using inotify-tools on CentOS, from installation to advanced configurations, ensuring that you can leverage its full potential. Introduction to inotify-tools Inotify-tools is a command-line utility that leverages the inotify (inode notify) feature of the Linux kernel, allowing you to monitor file system events. This is incredibly useful for tasks that require real-time responses to file changes, such as automatic backups, log monitoring, and dynamic content updates. Why Use inotify-tools on CentOS? CentOS is widely used in enterprise environments due to its stability and robust performance. By integrating inotify-tools, you can automate and...