Category Archives: Network

Internet Protocol v6

Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP) which was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion. IPv6 is intended to replace IPv4. IPv6 uses a 128-bit address, theoretically allowing 2128, or approximately 3.4×1038 addresses. The actual number is slightly smaller, as multiple ranges are reserved for special use or completely excluded from use. The total number of possible IPv6 address is more than 7.9×1028 times as many as IPv4, which uses 32-bit addresses and provides approximately 4.3 billion addresses. The two protocols are not designed to be interoperable, complicating the transition to IPv6. However, several IPv6 transition mechanisms have been devised to…

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Setup IPv6 NAT on OpenWRT Router

Introduction This tutorial is a HowTo for setting up IPv6 NAT on OpenWRT router.   The information of the environment is listed below. Network Environment: China Education and Research Network Center with dual stack IPv6 Network Device: NETGEAR R6100 (128M RAM) Firmware Version: OpenWrt Chaos Calmer 15.05 Install Dependencies for OpenWRT Login to OpenWRT router via SSH and run following commands: Setup IPv6 for Local-area Network Edit /etc/config/network, and add following lines in config interface 'lan': Remove following lines if exists: Edit /etc/config/dhcp, and change the content in  config dhcp 'lan' as follows: Setup Gateway for IPv6 Network Add following lines to /etc/firewall.user for forwarding IPv6 traffic: Setup up IPv6 gateway by creating file in /etc/hotplug.d/iface/90-ipv6 and adding following lines to the file: Then, add execute permission…

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HTTP Protocol

What's HTTP? HTTP stands for Hypertext Transfer Protocol. It's the network protocol used to deliver virtually all files and other data (collectively called resources) on the World Wide Web, whether they're HTML files, image files, query results, or anything else. Usually, HTTP takes place through TCP/IP sockets (and this tutorial ignores other possibilities). A browser is an HTTP client because it sends requests to an HTTP server (Web server), which then sends responses back to the client. The standard (and default) port for HTTP servers to listen on is 80, though they can use any port. Although I'll mention some details related to headers, it's best to instead consult the RFC (RFC 2616) for in-depth coverage. I will be pointing…

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How does Ajax Work

Ajax is a term coined by Jesse James Garrett and that became popular since the publication of the article Ajax: A New Approach to Web applications, published on February 2005, is a shortcut for: Asynchronous JavaScript and XML. The normal behavior of Internet that involves sending pages to the browser is completely changed by the use of Ajax. Ajax has become commonplace with its integration in HTML 5 and JavaScript frameworks, and in fact, the interest of developers has moved to HTML 5 for its new tags and APIs that accompany it. Among these, WebSocket appears as the successor to Ajax, because it is a superior means of communication between an application and the server or the backend. What's Ajax? Ajax…

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