Linux & Windows Tips, Tutorials, , Ideas

How do I create a symbolic links under Linux or Unix .

How do I create a symbolic links under Linux or Unix like operating systems using command line options? You need to use the ln command. It is a standard Unix / Linux / BSD command to create links to files. There are two types of links under UNIX, hard and soft link: Hard link vs.Read more about How do I create a symbolic links under Linux or Unix .[…]

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Linux: 20 Iptables Examples For New SysAdmins

 netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack.

This Linux based firewall is controlled by the program called iptables to handles filtering for IPv4, and ip6tables handles filtering for IPv6. I strongly recommend that you first read ourquick tutorial that explains how to configure a hostbased firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux. This post lists most simple iptables solutions required by a new Linux user to secure his or her Linux operating system from intruders.

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ss: Display Linux TCP / UDP Network and Socket Information

The ss command is used to show socket statistics. It can display stats for PACKET sockets, TCP sockets, UDP sockets, DCCP sockets, RAW sockets, Unix domain sockets, and more. It allows showing information similar to netstat command. It can display more TCP and state information than other tools. It is a new, incredibly useful and faster (as compare to netstat) tool for tracking TCP connections and sockets. SS can provide information about:

Read more about ss: Display Linux TCP / UDP Network and Socket Information

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Linux Iptables Limit the number of incoming tcp connection / syn-flood attacks

A SYN flood is a form of denial-of-service attack in which an attacker sends a succession of SYN requests to a target’s system. This is a well known type of attack and is generally not effective against modern networks. It works if a server allocates resources after receiving a SYN, but before it has receivedRead more about Linux Iptables Limit the number of incoming tcp connection / syn-flood attacks[…]

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Nginx: 413 Request Entity Too Large Error and Solution

I‘m running nginx as a frond end to php based Apache+mod_fastcgi server. My app lets user upload images upto 2MB in size. When users trying to upload 1.5MB+ size image file using nginx reverse proxy, they are getting the following error on screen:   Nginx 413 Request Entity Too Large How do I fix thisRead more about Nginx: 413 Request Entity Too Large Error and Solution[…]

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Top 20 Nginx WebServer Best Security Practices

Nginx is a lightweight, high performance web server/reverse proxy and e-mail (IMAP/POP3) proxy. It runs on UNIX, GNU/Linux, BSD variants, Mac OS X, Solaris, and Microsoft Windows. According to Netcraft, 6% of all domains on the Internet use nginx webserver. Nginx is one of a handful of servers written to address the C10K problem. UnlikeRead more about Top 20 Nginx WebServer Best Security Practices[…]

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