Introduction Controlling email flow within an organization is crucial for maintaining security and compliance. Zimbra Zimbra 8.6 offers robust features that allow administrators to restrict users from sending emails to specific domains or addresses.  This article will provide a step-by-step guide on how to implement these restrictions effectively, ensuring that your email system remains secure and well-regulated. How to restrict to user sending mail to certain domain. To configure on zimbra mta. Step 1: To add lines in file /opt/zimbra/conf/zmconfigd/smtpd_sender_restrictions.cf as bellow: #vi /opt/zimbra/conf/zmconfigd/smtpd_sender_restrictions.cf Adding lines the top as following: check_sender_access lmdb:/opt/zimbra/postfix/conf/restricted_senders Step 2: To add lines in file /opt/zimbra/conf/zmconfigd.cf vim /opt/zimbra/conf/zmconfigd.cf Adding the lines following before RESTART mta. POSTCONF smtpd_restriction_classes local_only     POSTCONF local_only ...

In my post, I demonstrate how to install and configure the BIND DNS server. I execute the following commands as the root account. Links to articles you may like: How to install php7 on centos 6 How to install and configure redmine on centos 6 How to owncloud 9 install ssl certificate centos 7 How To Install the BIND DNS Server on CentOS 6 KeepAlived IP Failover on CentOS & Red Hat To prepare package for BIND DNS server. yum update -y yum install bind bind-utils -y yum -y install perl perl-core wget openssh-clients openssh-server unzip nmap sysstat rsync telnet ntp ntpdate asia.pool.ntp.org service ntpd start chkconfig ntpd on To configure the static IP address: # vim /etc/sysconfig/network-scripts/ifcfg-eth1 The content is as follows: DEVICE=eth1 TYPE=Ethernet ONBOOT=yes NM_CONTROLLED=no BOOTPROTO=static IPADDR=192.168.131.10 NETMASK=255.255.255.0 GATEWAY=192.168.131.2 DNS=192.168.131.10 DNS1=8.8.8.8 DNS2=8.8.4.4 USERCTL=no PEERDNS=no To configure hosts file. vi...

Introduction iptables is a powerful tool for protecting Linux systems from unauthorized access and cyber threats.  In this article, we guide you through configuring and using iptables to manage firewall rules, from basic to advanced levels, ensuring maximum security for your server. Whether you're a beginner or an experienced system administrator, this post provides practical, detailed examples on how to use iptables to control IP access, manage ports, and set up effective connection limits for enhanced server protection.  You may reading link as below: Iptables how to How to reset password on centos 7 Bash script example 1. Basic iptables Rules Below is a sample iptables configuration to manage incoming and outgoing connections effectively: *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --d...

Introduction In small system, to install zimbra All-in-one in single server mail .In medium and large system zimbra mail server, to install and configure multi server (the more ldap, mta , mailbox install in server separate). in this my post, the tutorial install and configure zimbra multi server and   use demo zimbra 8.6  Let's go! Benefits of a Multi Server Setup A multi-server architecture for Zimbra offers several advantages: Scalability: Easily add servers to meet growing demands. Load Balancing: Distribute workloads efficiently. Reliability: Minimize downtime with redundancy. Specialization: Assign specific roles like mail store, LDAP, or MTA to individual servers for optimized performance. Prerequisites Before beginning the installation, ensure you have: Operating System: A compatible Linux distribution (e.g., CentOS, Ubuntu). DNS Configuration: Properly configured DNS records, including A and MX records. Hardware Requirements: Sufficient resources for ...

Introduction How to solved zimbra some services are not running. That after, to installed zimbra mail server. The display a some admin console status red in environment multiple server ( zimbra ldap, zimbra mailbox, zimbra mta etc.). Link to below you maybe likes: How to install and configure zimbra multi server.   How to restrict to user sending mail on zimbra 8.6. How to Restrict Sending to Distribution list in zimbra mail. How to change last login time for all accounts in zimbra ldap. How to zimbra reject authenticated sender login mismatch. Error zimbra some services are not running as bellow Step by step guide the solve problem zimbra some services are not running To restart and enable cron service the permanently. service crond restart chkconfig crond on Opening rsyslog.conf file and uncomment the following. vim /etc/rsyslog.conf Uncomment these two lines $modload imupd $UDPServerRun514   To restart and enable rsyslog service the permanently. servic...