Howto install and configure Postfix Mail Server on Fedora 18, install postfix mail server on Fedora 18, configure postfix. install postfix mail server on Centos 6. For those who plan to install postfix as an alternative, the can just uninstall the sendamil service to avoid port. How to Remove Sendmail Service From CentOS 5.5. Install Fail. 2ban (Intrusion Prevention) System on RHEL/Cent. OS 6. 3/5. 8, Fedora 1. Fail. 2ban is an open source free intrusion prevention framework developed in python programming language. Fail. 2ban operates by monitoring log files such as /var/log/pwdfail, /var/log/auth. IP address after too many password failure attempts. It used to update iptable firewall rules to reject the IP address for a specified amount of time. This article shows you how to install and configure Fail. RHEL 6. 3/6. 2/6. Cent. OS 6. 3/6. 2/6. Fedora 1. 7,1. 6,1. Fail. 2ban runs as a daemon that uses python scripts to parse log files for system intrusion attempts and adds a custom rules to iptables configuration file to ban the access to certain ip addresses. Install Fail. 2ban in Red. Hat / Cent. OS / Fedora. Before heading up for installation and configuration of Fail. Ban, I would like to tell you that most of the attackers trying to gain root access via SSH. So, I recommend you to pay close attention to things such as disable ssh root logins and use pair of ssh keys for authentication etc. Installing Fail. 2Ban in RHEL, Cent.
![]() ![]() OS and Fedora. By default Fail. Ban is not available under Linux systems, so you will need to add and enable third party RPMForge repository or EPEL repository in your Linux box. Once you’ve added repository, install it using following YUM command.# yum install fail. Configuring Default section for Fail. Ban. The master Fail. Ban configuration file is located under /etc/fail. So, open it using VI editor or any editor that you feel comfortable.# vi /etc/fail. Now, you will see default section with some basic rules that are followed by fail. If you want to add some extra layer of protection to your server, then you can customize the each rule section as per your needs.[DEFAULT]. IP address, a CIDR mask or a DNS host. Fail. 2ban will not. Several addresses can be. A host is banned if it has generated "maxretry" during the last "findtime". Let me describe each rule section with their description and what purpose we use these rules. Ignore. IP section allows you to white list certain IP addressess from blocking. Here, you can specify list of IP addresses with space separated and make sure you include your address. The number of seconds that a host would be banned from the server. The default is set for 6. The amount of time that a host has to log in. The default is set to 1. The number of failed login attempts before a host is blocked for the length of the ban time. Configuring ssh- iptables section for Fail. Ban. The following section is the default ssh- iptables section and it is turned on by default. So, you don’t need to make any changes to this section,[ssh- iptables]. SSH, port=ssh, protocol=tcp]. SSH, dest=root, [email protected]]. You can find the details of each rule described below. This section refers that SSH protection is on. You can turn it off by changing the word “true” to “false“. This section by default set to sshd and refers the config file (/etc/fail. This action tells the fail. IP address once a filter matches in the /etc/fail. If your server have mail setup, you can add email address, where fail. IP address. The sender section refers to file /etc/fail. The log path is the location of logs where fail. The max retry section is the same definition as the default option that we discussed above. Restarting Fail. 2Ban Service. Once you’ve made the changes to the fail. Fail. 2Ban service.# chkconfig - -level 2. Starting fail. 2ban: [ OK ]Verifying Fail. Ban iptables rules. Check the rules that fail. IP table section.# iptables - LI have made some failed login attempts from one of our server to the server where fail. You see the banned IP address of my server. Message from [email protected] at Nov 2. WARNING [ssh- iptables] Ban 1. Chain INPUT (policy ACCEPT). SSH tcp - - anywhere anywhere tcp dpt: ssh. ACCEPT all - - anywhere anywhere state RELATED,ESTABLISHED. ACCEPT icmp - - anywhere anywhere. ACCEPT all - - anywhere anywhere. ACCEPT tcp - - anywhere anywhere state NEW tcp dpt: ssh. ACCEPT tcp - - anywhere anywhere state NEW tcp dpt: http. ACCEPT tcp - - anywhere anywhere state NEW tcp multiport dports 5. REJECT all - - anywhere anywhere reject- with icmp- host- prohibited. Chain FORWARD (policy ACCEPT). REJECT all - - anywhere anywhere reject- with icmp- host- prohibited. Chain OUTPUT (policy ACCEPT). Chain fail. 2ban- SSH (1 references). DROP all - - 1. 5. RETURN all - - anywhere anywhere. Watch Failed SSH login attempts. To see the current ssh failed login attempts, run the following command it will display a list of failed attempts attempted by hosts.# cat /var/log/secure | grep 'Failed password' | sort | uniq - c. Nov 1. 9 1. 6: 5. Failed password for root from 1. Nov 2. 3 1. 3: 5. Failed password for root from 1. Nov 2. 3 1. 3: 5. Failed password for root from 1. Nov 2. 3 1. 3: 5. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Oct 1. 8 1. 4: 1. Failed password for root from 1. Remove IP Address from Fail. Ban. To remove the banned IP address from the fail. Run the following command.# iptables - D fail. For any additional information, please visit Fail. If you are having any questions any comments about this article, please tell us via comments. How to Install Postfix on Cent. OS/RHEL 7/6/5. Postfix is fast and popular SMTP server widely used. The main job of postfix is to relay mail locally or to intended destination outside the network. Some of the most popular SMTP servers are Sendmail, Postfix and Qmail. By default Sendmail comes pre- installed with Cent. OS/RHEL 5. We will need to remove it and install Postfix. Step 1: Install Postfix If Postfix not already installed on your machine, Install it using following command. Also remove sendmail if already installed.# yum remove sendmail. Make postfix as default MTA for your system using following command# alternatives - -set mta /usr/sbin/postfix. If above command not work and you get output as “/usr/sbin/postfix has not been configured as an alternative for mta“. Use below command to do the same else skip it# alternatives - -set mta /usr/sbin/sendmail. Step 2: Configure Postfix Let’s start postfix configuration. Edit Postfix configuration file /etc/postfix/main. Maildir/. After executing above command edit postfix configuration file and make sure all changes done properly. Step 3: Restart Postfix Service As we have done basic Postfix configuration, So restart Postfix service to read changes of configuration. Also configure to auto start on system boot.# service postfix restart. Step 4: Open Firewall Port Now if your system is configured to use iptables firewall, So add firewall rules to make postfix accessible from outside, using following commands.# iptables - A INPUT - m state - -state NEW - m tcp - p tcp - -dport 2. ACCEPT. # iptables - A INPUT - m state - -state NEW - m udp - p udp - -dport 2. ACCEPT. Thanks for using this article.
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