Skip to main content

1.1.4 Configuring NAT and PAT


1.1.4 Configuring NAT and PAT
Static Translation
To configure static inside source address translation, perform the tasks in Figures and .
Figure shows the use of static NAT translation. The router will translate packets from host 10.1.1.2 to a source address of 192.168.1.2.


Dynamic Translation
To configure dynamic inside source address translation, perform the tasks in Figure .
The access list must permit only those addresses that are to be translated. Remember that there is an implicit “deny all” at the end of each access list. An access list that is too permissive can lead to unpredictable results. Cisco advises against configuring access lists referenced by NAT commands with the permit any command. Using permit any can result in NAT consuming too many router resources, which can cause network problems.
Figure translates all source addresses passing access list 1, which have source address from 10.1.0.0/24, to an address from the pool named nat-pool1. The pool contains addresses from 179.9.8.80/24 to 179.9.8.95/24.
NOTE:
NAT will not translate the host 10.1.1.2, as it is not permitted for translation by the access list.


Overloading
Overloading is configured in two ways depending on how public IP addresses have been allocated. An ISP can allocate a network only one public IP address, and this is typically assigned to the outside interface which connects to the ISP. Figure shows how to configure overloading in this situation.
Another way of configuring overload is if the ISP has given one or more public IP addresses for use as a NAT pool. This pool can be overloaded as shown in the configuration in Figure .
Figure shows an example configuration of PAT.

Comments

Post a Comment

Popular posts from this blog

OSI layers / Peer-to-peer communications / TCP/IP model

OSI layers 2.3.4 This page discusses the seven layers of the OSI model. The OSI reference model is a framework that is used to understand how information travels throughout a network. The OSI reference model explains how packets travel through the various layers to another device on a network, even if the sender and destination have different types of network media. In the OSI reference model, there are seven numbered layers, each of which illustrates a particular network function. - Dividing the network into seven layers provides the following advantages: • It breaks network communication into smaller, more manageable parts. • It standardizes network components to allow multiple vendor development and support. • It allows different types of network hardware and software to communicate with each other. • It prevents changes in one layer from affecting other layers. • It divides network communication into smaller parts to make learning it easier to understand. In the foll...
Post a Comment
Read more

PC Basic...

• Backplane – A backplane is an electronic circuit board containing circuitry and sockets into which additional electronic devices on other circuit boards or cards can be plugged; in a computer, generally synonymous with or part of the motherboard. • Network interface card (NIC) – An expansion board inserted into a computer so that the computer can be connected to a network. • Video card – A board that plugs into a PC to give it display capabilities. • Audio card – An expansion board that enables a computer to manipulate and output sounds. • Parallel port – An interface capable of transferring more than one bit simultaneously that is used to connect external devices such as printers. • Serial port – An interface that can be used for serial communication in which only one bit is transmitted at a time. • Mouse port – A port used to connect a mouse to a PC. • USB port – A Universal Serial Bus connector. A USB port connects devices such as a mouse or printer to the computer ...
Post a Comment
Read more

1.2.2 RIP V2 Features

 1.2.2 RIP V2 Features This page will discuss RIP v2, which is an improved version of RIP v1. Both versions of RIP share the following features: It is a distance vector protocol that uses a hop count metric. It uses hold down timers to prevent routing loops – default is 180 seconds. It uses split horizon to prevent routing loops. It uses 16 hops as a metric for infinite distance. RIP v2 provides prefix routing, which allows it to send out subnet mask information with the route update. Therefore, RIP v2 supports the use of classless routing in which different subnets within the same network can use different subnet masks, as in VLSM. RIP v2 provides for authentication in its updates. A set of keys can be used on an interface as an authentication check. RIP v2 allows for a choice of the type of authentication to be used in RIP v2 packets. The choice can be either clear text or Message-Digest 5 (MD5) encryption. Clear text is the default. MD5 can be used t...
Post a Comment
Read more