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Policy-based Routing
In computer networking, policy-based routing (PBR) is a technique used to make routing decisions based on policies set by the network administrator. When a router (computing), router receives a packet it normally decides where to forward it based on the destination address in the packet, which is then used to look up an entry in a routing table. However, in some cases, there may be a need to forward the packet based on other criteria. For example, a network administrator might want to forward a packet based on the source address, not the destination address. This permits routing of packets originating from different sources to different networks even when the destinations are the same and can be useful when interconnecting several private networks. Policy-based routing may also be based on the size of the packet, the protocol of the payload, or other information available in a packet header or payload. In the Cisco IOS, PBR is implemented using ''route maps''. Linux supports m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Networking
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Routing
Routing is the process of selecting a path for traffic in a Network theory, network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone network (PSTN), and computer networks, such as the Internet. In packet switching networks, routing is the higher-level decision making that directs network packets from their source toward their destination through intermediate network nodes by specific packet forwarding mechanisms. Packet forwarding is the transit of network packets from one Network interface controller, network interface to another. Intermediate nodes are typically network hardware devices such as Router (computing), routers, gateway (telecommunications), gateways, Firewall (computing), firewalls, or network switch, switches. General-purpose computers also forward packets and perform routing, although they have no specially optimized hardware for the task. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Router (computing)
A router is a computer and networking device that Packet forwarding, forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination Node (networking), node. The most familiar type of Internet Protocol, IP routers are Residential gateway, home and small office routers that forward IP packet (other), IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Routing Table
In computer networking, a routing table, or routing information base (RIB), is a data table stored in a router or a network host that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes. The routing table contains information about the topology of the network immediately around it. The construction of routing tables is the primary goal of routing protocols. Static routes are entries that are fixed, rather than resulting from routing protocols and network topology discovery procedures. Overview A routing table is analogous to a distribution map in package delivery. Whenever a node needs to send data to another node on a network, it must first know ''where'' to send it. If the node cannot directly connect to the destination node, it has to send it via other nodes along a route to the destination node. Each node needs to keep track of which way to deliver various packages of data, and for this it uses a ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Routing
In computer networking, source routing, also called path addressing, allows a sender of a data packet to partially or completely specify the route the packet takes through the network. In contrast, in conventional routing, routers in the network determine the path incrementally based on the packet's destination. Another routing alternative, label switching, is used in connection-oriented networks such as X.25, Frame Relay, Asynchronous Transfer Mode and Multiprotocol Label Switching. Source routing allows easier troubleshooting, improved traceroute, and enables a node to discover all the possible routes to a host. It does not allow a source to directly manage network performance by forcing packets to travel over one path to prevent congestion on another. Many high-performance interconnects including Myrinet, Quadrics, IEEE 1355, and SpaceWire support source routing. Internet Protocol In the Internet Protocol, two header options are available which are rarely used: " strict so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisco IOS
The Internetworking Operating System (IOS) is a family of proprietary network operating systems used on several router and network switch models manufactured by Cisco Systems Cisco Systems, Inc. (using the trademark Cisco) is an American multinational corporation, multinational digital communications technology conglomerate (company), conglomerate corporation headquartered in San Jose, California. Cisco develops, m .... The system is a package of routing, switching, internetworking, and telecommunications functions integrated into a computer multitasking, multitasking operating system. Although the IOS code base includes a cooperative multitasking kernel, most IOS features have been ported to other kernels, such as Linux and QNX, for use in Cisco products. Not all Cisco networking products run IOS. Exceptions include some Cisco Catalyst switches, which run Cisco IOS XE, IOS XE, and Cisco ASR routers, which run either IOS XE or Cisco IOS XR, IOS XR; both are Linux-based op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ipfirewall
ipfirewall or ipfw is a FreeBSD IP, stateful firewall, packet filter and traffic accounting facility. Its ruleset logic is similar to many other packet filters except IPFilter. ipfw is authored and maintained by FreeBSD volunteer staff members. Its syntax enables use of sophisticated filtering capabilities and thus enables users to satisfy advanced requirements. It can either be used as a loadable kernel module or incorporated into the kernel; use as a loadable kernel module where possible is highly recommended. ipfw was the built-in firewall of Mac OS X until Mac OS X 10.7 Lion in 2011 when it was replaced with the OpenBSD project's PF. Like FreeBSD, ipfw is open source. It is used in many FreeBSD-based firewall products, including m0n0wall and FreeNAS. A port of an early version of ipfw was used since Linux 1.1 as the first implementation of firewall available for Linux, until it was replaced by ipchains. A modern port of ipfw and the ''dummynet'' traffic shaper is av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PF (firewall)
PF (Packet Filter, also written pf) is a BSD licensed stateful packet filter, a central piece of software for firewalling. It is comparable to netfilter (iptables), ipfw, and ipfilter. PF was developed for OpenBSD, but has been ported to many other operating systems. History PF was originally designed as replacement for Darren Reed's IPFilter, from which it derives much of its rule syntax. IPFilter was removed from OpenBSD's CVS tree on 30 May 2001 due to OpenBSD developers' concerns with its license. The initial version of PF was written by Daniel Hartmeier. It appeared in OpenBSD 3.0, which was released on 1 December 2001. It was later extensively redesigned by Henning Brauer and Ryan McBride with most of the code written by Henning Brauer. Henning Brauer is currently the main developer of PF. Features The filtering syntax is similar to IPFilter, with some modifications to make it clearer. Network address translation (NAT) and quality of service (QoS) have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
