Description
ufw is stands for Uncomplicated Firewall, this program is for managing a Linux firewall and aims to provide an easy to use interface for the user, as well as support package integration and dynamic-detection of open ports. ufw  is not intended to provide complete firewall functionality via its command interface, but instead provides an easy […]

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There is no straight forward method for 301/302 URL redirection as we did with rewrite rule. But there are some situations where we need to redirect a URL on a host to some URL on different host. In this situation we need to use 301/302 redirection.  There are two ways we can implement this.
First method […]

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Varnish is a reverse proxy or http accelerator that uses serverside caching to increase the speed of servicing HTTP requests for use in things such as websites. The varnishd daemon accepts HTTP requests from clients, passes them on to […]

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Introduction
OpenNTPD is a Unix system daemon implementing the Network Time Protocol to synchronize the local clock of a computer system with remote NTP servers.
OpenNTPD is primarily developed by Henning Brauer as part of the OpenBSD project. Its design goals include being secure (non-exploitable), easy to configure, accurate enough for most purposes and with source code […]

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Introduction
httperf is a tool to measure web server  performance.
Example
$ httperf –server haproxy.com –port=80 –uri /frontend_dev.php –num-conns=25
httperf –client=0/1 –server=haproxy.com –port=80 –uri=/frontend_dev.php –send-buffer=4096 –recv-buffer=16384 –num-conns=25 –num-calls=1
Maximum connect burst length: 1

Total: connections 25 requests 25 replies 25 test-duration 0.528 s

Connection rate: 47.4 conn/s (21.1 ms/conn, <=1 concurrent connections)
Connection time [ms]: min 4.9 avg 21.1 max 408.2 median 4.5 […]

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What is Port Forwarding?
Port forwarding is a feature of the IPTables system. It allows one computer to forward connections made to it so that another computer can actually process the request. If you want a very simple metaphor you can think of it as mail forwarding. Each computer has a number of […]

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In Linux there has a number of useful bandwidth monitoring tools such as nload, netwatch, iftop, trafshow, bandwidthd, vnstat. If all you need is a basic overview of your total bandwidth usage, iptables is all you really need. Usually we use iptables for setting firewall and port forwardings, but iptables also provides packet and byte […]

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Logrotate
Log files are important for Linux system security and trouble shooting.  Log files tend to grow, and if a log grows too much you compress it and takes the backup. Logrotate enables you to do this in a much better way. The process that is in charge of compressing and rotating these logfiles is called […]

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Haproxy
HAProxy is a free, very fast and reliable solution offering high availability, load balancing, and proxying for TCP and HTTP-based applications. It is particularly suited for web sites crawling under very high loads while needing persistence or Layer7 processing. Supporting tens of thousands of connections is clearly realistic with todays hardware. Its mode of operation […]

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Monitoring services using Mon
mon is a general-purpose scheduler and alert management tool used for monitoring service availability and
triggering alerts upon failure detection.
Mon uses some Linux command and services such as ping command to check host connectivity and mail servers for sending mail, so you must install postfix and other packages so that mon should work […]

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