Unlike the ip default-gateway command, you can use ip default-network when ip routing is enabled on the Cisco router. When you configure ip default-network the router considers routes to that network for installation as the gateway of last resort on the router. For every network configured with ip default-network, if a router has a route to that network, that route is flagged as a candidate default route. This network diagram displays the routing table taken from router 2513: Note the static route to 198.10.1.0 via 161.44.192.2 and that the gateway of last resort is not set.
http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/16448-default.html
The ip default-gateway command differs from the other two commands. It should only be used when ip routing is disabled on the Cisco router. For instance, if the router is a host in the IP world, you can use this command to define a default gateway for it. You might also use this command when your low end Cisco router is in boot mode in order to TFTP a Cisco IOS® Software image to the router.
http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/16448-default.html
Without a default route, a router will drop a request for a network that isn't in its routing table and send ICMP Destination Unreachable to the source of the traffic. Here's a simple example: Our PC has an IP address of 192.168.1.100 and a subnet mask of 255.255.255.0. Let's say we want to talk to a server on the LAN, which has an IP address of 192.168.1.200. For this, we actually don't need a default route or default gateway configured on the PC.
http://www.techrepublic.com/article/cisco-administration-101-what-you-need-to-know-about-default-routes/
While you can't tell it from the output, we obtained both the default route and default gateway in our examples via Dynamic Host Configuration Protocol (DHCP). There are actually three ways to obtain a default route. 1  Configure a static route.
http://www.techrepublic.com/article/cisco-administration-101-what-you-need-to-know-about-default-routes/
Just as a PC has a default gateway to get to its local router &#8212 and therefore to the Internet &#8212 many routers and switches also have default routes to access networks that aren't local.
http://www.techrepublic.com/article/cisco-administration-101-what-you-need-to-know-about-default-routes/
Typically in a TCP/IP network, nodes such as servers, workstations and network devices each have a defined default route setting, (pointing to the default gateway), defining where to send packets for IP addresses for which they can determine no specific route. The gateway is by definition a router.
https://en.wikipedia.org/wiki/Default_gateway
A default gateway in computer networking is the node that is assumed to know how to forward packets on to other networks.
https://en.wikipedia.org/wiki/Default_gateway
Here's an example of configuring a default route on a router or switch: Here's what this command says: For all traffic that doesn't go to one of the locally connected networks, forward it to the router at IP address 1.1.1.1.
http://www.techrepublic.com/article/cisco-administration-101-what-you-need-to-know-about-default-routes/
In a home or small office environment, the device, such as a DSL router or cable router that connects the local network to the Internet will act as the default gateway for all network devices. In enterprise systems, there may be many internal network segments.
https://en.wikipedia.org/wiki/Default_gateway
Instead it must be sent to the default gateway for further routing to their ultimate destination. In this example, the default gateway uses the IP address 192.168.4.1, which is resolved into a MAC address with ARP in the usual way.
https://en.wikipedia.org/wiki/Default_gateway
is a default gateway a router
No, A default gateway is not a router. No, a default gateway is not a router.