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In computer networking, the default route is a configuration of the Internet Protocol (IP) that establishes a forwarding rule for packets when no specific address of a next-hop host is available from the routing table or other routing mechanisms.
The default route is generally the address of another router, which treats the packet the same way: if a route matches, the packet is forwarded accordingly, otherwise the packet is forwarded to the default route of that router. The route evaluation process in each router uses the longest prefix match method to obtain the most specific route. The network with the longest subnet mask or network prefix that matches the destination IP address is the next-hop network gateway. The process repeats until a packet is delivered to the destination host, or earlier along the route, when a router has no default route available and cannot route the packet otherwise. In the latter case, the packet is dropped and an ICMP Destination Unreachable message may be returned.[1] Each router traversal counts as one hop in the distance calculation for the transmission path.
The device to which the default route points is often called the default gateway, and it often carries out other functions such as packet filtering, firewalling, or proxy server operations.
The default route in Internet Protocol Version 4 (IPv4) is designated as the zero address, 0.0.0.0/0 in CIDR notation.[2] Similarly, in IPv6, the default route is specified by ::/0. The subnet mask is specified as /0, which effectively specifies all networks and is the shortest match possible. A route lookup that does not match any other rule falls back to this route.
In the highest-level segment of a network, administrators generally point the default route for a given host towards the router that has a connection to a network service provider. Therefore, packets with destinations outside the organization's LAN, typically destinations on the Internet or a wide area network, are forwarded to the router with the connection to that provider.
^J. Postel (September 1981). INTERNET CONTROL MESSAGE PROTOCOL, DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION. Network Working Group. doi:10.17487/RFC0792. RFC 792.
^V. Fuller; T. Li (August 2006). Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan. Network Working Group. doi:10.17487/RFC4632. RFC 4632. Note that the degenerate route to prefix 0.0.0.0/0 is used as a default route and MUST be accepted by all implementations.
is available from the routing table or other routing mechanisms. The defaultroute is generally the address of another router, which treats the packet...
A default gateway is the node in a computer network using the Internet protocol suite that serves as the forwarding host (router) to other networks when...
on a defaultroute. An ABR deletes type 4 and 5 LSAs from internal routers, sends them a defaultroute of 0.0.0.0 and turns itself into a default gateway...
configured as the defaultroute in this example. A defaultroute is recognized by the destination 0.0.0.0 and the flag G. A network router is identified by...
typically propagated by default to other peers: New routes learned from an eBGP peer are re-advertised to all iBGP and eBGP peers. New routes learned from an...
(LAN) that connects to the corporate network by only one router, or multiple defaultrouters connected to the same logical upstream destination. A single...
routing table, the router uses the route with the lowest administrative distance. Router vendors typically design their routers to assign a default administrative...
define an exit point from a router when no other routes are available or necessary. This is called a defaultroute. Static routing can be used for small networks...
configurable hop count of IGRP-routed packets is 255 (default 100), and routing updates are broadcast every 90 seconds (by default). IGRP uses protocol number...
Internet Protocol version 6 (IPv6) hosts with IP addresses, IP prefixes, defaultroute, local segment MTU, and other configuration data required to operate...
were using the default credentials for their NetGear switch. Some devices (such as wireless routers) will have unique defaultrouter usernames and passwords...
making the route more specific. Forwarding tables often contain a defaultroute, which has the shortest possible prefix match, to fall back on in case...
Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections...
ISPs' routes (usually but not necessarily in the form of a defaultroute or a full set of routes to all of the destinations on the Internet) to the ISP's...
specifies how long a routing entry can be in the routing table without being updated. This is also called as expiration Timer. By default, the value is 180...
aware of all routes. Routers that lie within a LAN only know about routes in the LAN. Unrecognized destinations are passed to the defaultroute. This article...
it may use: default or static routes that are manually configured, on-demand routing, dynamic routing protocols, or Policy-based routing. In a small network...
networking, the Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol for establishing a fault-tolerant default gateway. Version 1 of...
table that associates each routing prefix with a precedence level. The default table has the following content: The default configuration places preference...
Virginia and West Virginia use the default for their secondary state routes but different designs for their primary state routes. There are several additional...
products.... Route filtering and the use of a defaultroute can also be used to decrease the number of routes in an affected device. Lagerholm, Stephan....
state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either...
journey, there is a defaultroute, possibly with other routes distinguished by intermediate touches, in the fare database. Each route has an associated...
subnetwork. Routing tables are maintained by manual configuration or automatically by routing protocols. End-nodes typically use a defaultroute that points...
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