Understanding the Linux chattr Command: A Comprehensive Guide

chattr

Introduction This guide introduces you to the chattr command in Linux. While many Linux users know about file permissions, few discuss the additional control attributes offer. You can manipulate these attributes using the chattr command. What is chattr? The chattr command allows you to change file attributes on a Linux file system. These attributes can … Read more

ModSecurity: Request body no files data length is larger than the configured limit (1048576)

ModSecurity: Request body no files data length is larger than the configured limit

ModSecurity, an open-source web application firewall (WAF), provides valuable tools to defend web applications from a myriad of online threats. However, as is common with any complex tool, problems can sometimes arise. One such issue relates to the request body size, which can trigger an error if the data length exceeds the configured limit. The … Read more

IPSET with IPTABLES

ipset with iptables

IPSET is an extension to iptables that allows you to create firewall rules that match entire “sets” of addresses at once. Unlike normal iptables chains, which are stored and traversed linearly, IP sets are stored in indexed data structures, like addresses, networks, (TCP/UDP) port numbers, MAC addresses, interface names or combinations of them in a … Read more

Postfix – Configuration Tips to Fight Spam

Postfix Configuration Tips to Fight Spam

In this guide you will learn how to tweak the default postfix configuration for incoming emails. In Postfix configuration you need to add or edit following directives on /etc/postfix/main.cf configuration file. All configuration directives are explained in the postfix website. Postfix Configuration Parameters smtpd_helo_required = yes Require that a remote SMTP client introduces itself with … Read more

Extending ClamAV Signatures with RFXN Database for PHP Malware’s

extending clamav signatures

You can use 3rd party compiled malware and virus signature databases to extend ClamAV signature database collection with better detection PHP malware. RFXN (R-FX NETWORKS) Database signatures are updated typically once per day or more frequently depending on incoming threat data from the LMD checkout feature, IPS malware extraction, and other sources. Malware.Expert also generates … Read more

Add RBL list to cPanel server

Add RBL list to cPanel server

This tutorial we show how you can use the RBLs interface to configure your mail server to check incoming mail against the available RBLs. Your server will block the incoming messages if the IP address or hostname matches an cPanel RBL entry. RBL is short for “Real-time Blackhole List.” RBL servers keep lists of spam-heavy … Read more

Install IPSET to CSF Firewall

install ipset to csf

Servers running iptables with CSF firewall can become slow and bogged down while processing the sometimes hundreds of IP addresses in CSF’s iptables chains. Thankfully, it is possible to quickly and easily alleviate this slowdown by installing and configuring a took called ipset. IP sets are a framework inside the Linux kernel that can store … Read more