70-291: MCSE Guide to Managing a Microsoft Windows Server 2003 Network Chapter 12: Routing

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 2 Objectives Configure Windows Server 2003 as a router Interpret and manage routing tables Describe the function of dynamic routing Implement a dynamic routing protocol on Windows Server 2003 Control traffic sent through a router using packet filters Create and configure demand-dial connections for routing Troubleshoot routing

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 3 Configure Routers A router is a network device that moves packets from one network to another TCP/IP, IPX/SPX, and AppleTalk can be routed Windows Server 2003 can be used as a router Windows Server 2003 does not support IPX/SPX routing Cheaper to configure existing server as a router than buying a dedicated piece of hardware

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 4 Configuring Routers (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 5 Configuring Routers (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 6 Routing Tables Responsible for making intelligent decisions about how to move packets from one network to another in the fastest way possible List of networks known to the router Each network entry called a route Windows Server 2003 automatically configures default gateway route and routes to local networks from TCP/IP properties for each network interface Static routing is used when security is required otherwise dynamic routing is used

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 7 Routing Tables (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 8 Routing Tables (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 9 Routing Tables (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 10 Routing Protocols Responsible for calculating best path from one network to another and advertising routes for dynamic routing Each routing protocol uses a different algorithm Each protocol advertises different amounts of information and with a different frequency Two protocols are used in Windows Server 2003 for IP routing: Routing Information Protocol (RIP) Open Shortest Path First (OSPF)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 11 RIP Simplest of the two routing protocols and most popular No configuration necessary under most circumstances Distance-vector routing protocol Does not differentiate between different link speeds Each router sends broadcast packet every 30 seconds

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 12 RIP (continued) Many options that can be configured Type of events to be logged can be configured Configure from which IP addresses this router accepts updates Can use broadcasts or multicasts when sending information to other RIP routers Rip routers advertise the routes learned from other routers

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 13 RIP (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 14 RIP (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 15 RIP (continued) Can force authentication between routers when announcements are sent Password for authentication is plain text Can configure which incoming and outgoing routes are accepted Split-horizon processing stops information from going back in the direction it was received from Poison-reverse processing marks a network as unreachable if it goes down

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 16 RIP (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 17 RIP (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 18 RIP (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 19 OSPF Link-state routing algorithm Determines the best path from one network to another based on a configurable value called cost More flexible than RIP Not normally implemented on Windows Server 2003 An OSPF router sends only changes in its routing table when communicating with other routers

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 20 Filtering Router Traffic Can control packets allowed to pass between routed networks using packet filters Packet filters are directional Packet filters are used to filter network traffic based on criteria such as: Protocol Source address Destination address Port number

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 21 Filtering Router Traffic (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 22 Configuring Packet Filters

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 23 Configuring Packet Filters (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 24 Configuring Packet Filters (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 25 Demand-dial Connections Used to establish a connection between two routers only when there is data to send Traditionally used to minimize the amount of phone time used on dial-up connections between routers Can also be used to initiate VPN connections between Windows routers Can be created for PPPoE connections

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 26 Creating Demand-dial Connections For a demand-dial connection to function properly: Enable the server to perform demand-dial routing Configure a port to allow demand-dial routing Create a demand-dial interface New demand-dial connections are created using the Demand-Dial Interface Wizard

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 27 Creating Demand-dial Connections (continued) A user account with remote access permission is required to establish a demand-dial connection Avoid sending plain-text passwords At least one static route is required to trigger the demand-dial interface

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 28 Configure Demand-dial Settings Most options can be configured during creation, but some options can be configured only after creation You can configure security settings and idle timeout You can configure a set of dial-out hours

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 29 Configure Demand-dial Settings (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 30 Configure Demand-dial Settings (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 31 Demand-dial Filters With the default configuration, a demand-dial connection is triggered by any IP traffic that needs to be routed Filters control which types of network traffic trigger a demand-dial connection Configured the same way as a firewall rule Can be used with a dial-up Internet connection to ensure that the connection is not dialed except for allowed traffic

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 32 Demand-dial Filters (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 33 Demand-dial Filters (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 34 Troubleshooting Routing Most problems result from an incorrect configuration First place to check for problems is the routing table A remote router may prevent a packet from reaching its destination network Can use the tracert command to see the path a packet takes from one router to another

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 35 Troubleshooting Routing (continued)

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 36 Summary Windows Server 2003 can be configured as a low- cost router for TCP/IP and AppleTalk Each router maintains a routing table that stores routes to local and remote networks Entries in the routing table may be configured automatically, using the route command, using the Routing and Remote Access snap-in, or by using a dynamic routing protocol

70-291: MCSE Guide to Managing a Microsoft Windows Server Network 37 Summary (continued) RIP is a distance-vector routing algorithm that calculates paths based on hops OSPF is a link-state routing algorithm that calculates paths based on a configurable metric called cost Packet filters may be applied to network interfaces on a router to control the flow of IP packets Demand-dial connections are activated only when network traffic requires them The tracert command may be used to list the routers a packet crosses to reach a destination computer