Module 16: Troubleshoot Static And Default Routes
Module 16: Troubleshoot Staticand Default RoutesInstructor MaterialsSwitching, Routing and Wireless Essentials v7.0(SRWE)
Module 16: TroubleshootStatic and Default RoutesSwitching, Routing and WirelessEssentials v7.0 (SRWE)
Module ObjectivesModule Title: Troubleshoot Static and Default RoutesModule Objective: Troubleshoot static and default route configurations.Topic TitlePacket Processing with Static RoutesTopic ObjectiveExplain how a router processes packets when a static routeis configured.Troubleshoot IPv4 Static and Default RouteConfigurationTroubleshoot common static and default route configurationissues. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential9
16.1 Packet Processing withStatic Routes 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential10
Packet Processing with Static RoutesStatic Routes and Packet Forwarding PC1 addresses a packet to PC3 and sends it to thedefault gateway address. When the packet arrives on the R1 G0/0/0 interface,R1 decapsulates the packet and searches the routingtable for a matching destination network entry.If the destination IP address: Matches a static route entry, R1 will use the static route to identify the next-hop IP address or exitinterface. Does not match a specific route to the destination network, then R1 will use the default static route(if configured). Does not match a route table entry, then R1 will drop the packet and send an ICMP message backto the source (i.e., PC1). 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential11
Packet Processing with Static RoutesStatic Routes and Packet Forwarding (Cont.)Assuming R1 matched a routing table entry, itencapsulates the packet in a new frame andforwards it out of interface S0/1/0 to R2. R2 receives the packet on its S0/1/0 interface. It decapsulates and processes the packet thesame way R1 did. When R2 finds a match in the routing table, it usesthe identified next-hop IP address or exit interfaceand sends the packet out of its interface S0/1/1towards R3. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential12
Packet Processing with Static RoutesStatic Routes and Packet Forwarding (Cont.) R3 receives the packet, decapsulates it, andsearches the routing table for a match. The destination IP address of PC3 matches thedirectly connected G0/0/0 interface. Therefore, R3searches the ARP table for the Layer 2 MACaddress of PC3. If no ARP entry exists, then R3 sends an ARPrequest out of the G0/0/0 interface. PC3 responds with an ARP reply containing its MAC address. R3 encapsulates the packet in a new frame and uses the PC3 MAC address as thedestination MAC address and the G0/0/0 MAC address as the source MAC address. The frame is forwarded out of interface G0/0/0 and PC3 receives and processes itaccordingly. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential13
16.2 Troubleshoot IPv4 Staticand Default RouteConfiguration 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential14
Troubleshoot IPv4 Static and Default Route ConfigurationNetwork ChangesNetworks fail for a number of reasons: An interface can fail A service provider drops a connection Links can become oversaturated An administrator may enter a wrong configuration.Network administrators are responsible for pinpointing and solving the problem.To efficiently find and solve these issues, it is advantageous to be intimately familiar withtools to help isolate routing problems quickly. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential15
Troubleshoot IPv4 Static and Default Route ConfigurationCommon Troubleshooting CommandsCommandDescriptionping Verify Layer 3 connectivity to destination. Extended pings provide additional options.traceroute Verify path to destination network. It uses ICMP echo reply messages to determine the hops tothe destination.show ip route Displays the routing table. Used to verify route entries for destination IP addresses.show ip interface brief Displays the status of device interfaces. Used to verify the operational status and IP address of aninterface.show cdp neighbors Displays a list of directly connected Cisco devices. Also used to validate Layer 1 and 2 connectivity. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential16
Troubleshoot IPv4 Static and Default Route ConfigurationSolve a Connectivity ProblemConnectivity from PC1 to PC3 fails. Extended pings from the R1 G0/0/0 interface to PC3 fail.Pings from R1 (i.e., S0/1/0 interface) to R2 aresuccessful.Pings from R1 (i.e., S0/1/0 interface) to R3 aresuccessful.R2 routing table reveals the problemand the incorrect static route isremoved.A new static route solves the problem. ip route 172.16.3.0 255.255.255.0 172.16.2.1R2# show ip route begin GatewayGateway of last resort is not set172.16.0.0/16 is variably subnetted, 5 subnets, 2 masksC172.16.1.0/24 is directly connected, GigabitEthernet0/0/0L172.16.1.1/32 is directly connected, GigabitEthernet0/0/0C172.16.2.0/24 is directly connected, Serial0/l/0L172.16.2.2/32 is directly connected, Serial0/l/0S172.16.3.0/24 [1/0] via 192.168.1.1192.168.1.0/24 is variably subnetted, 2 subnets, 2 masksC192.168.1.0/24 is directly connected, Serial0/1/1L192.168.1.2/32 is directly connected, Serial0/1/1S192.168.2.0/24 [1/0] via 192.168.1.1R2# 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential17
16.3 Module Practice and Quiz 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential18
Structured DesignPacket Tracer – Troubleshoot Static and Default RoutesIn this activity you will troubleshoot and static and default routes and repair any errors thatyou find. Troubleshoot IPv4 static routes. Troubleshoot IPv6 static routes. Configure IPv4 static routes. Configure IPv4 default routes. Configure IPv6 static routes. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential19
Structured DesignLab - Troubleshoot Static and Default RoutesIn this lab, you will complete the following objectives: Evaluate Network Operation. Gather information, create an action plan, and implement corrections. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential20
Module Practice and QuizWhat did I learn in this module? A host sends a packet to another host and sends it to the default gateway address. When the packet arrives on a router interface, it decapsulates the packet and searches therouting table for a matching destination network entry. If the destination IP address: Matches a static route entry, the router will use the static route to identify the next hop IP address or exitinterface. Does not match a specific route to the destination network, then the router will use the default staticroute (if configured). Does not match a route table entry, then the router will drop the packet and send an ICMP messageback to the source. If the router matched a routing table entry, then the router encapsulates the packet andforwards it out of the appropriate interface. The packet is forwarded from router to router until it reaches its destination network. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential21
Module Practice and QuizWhat did I learn in this module? (Cont.) When the packet reaches the destination network, that router will search the routing table fora match. When the destination IP address matches a directly connected Ethernet interface, the routersearches the ARP table for the Layer 2 MAC address of the destination IP address. If no ARP entry exists, the router sends an ARP request out of the Ethernet interface The destination host responds with an ARP reply containing its MAC address. The router then encapsulates the packet in a new frame. It uses the MAC address of thedestination host as the frame destination MAC address, and the MAC address of the routerEthernet interface as the source MAC address in the frame. The frame is forwarded out of the appropriate interface. The packet arrives on the network interface card (NIC) interface of destination host and isprocessed accordingly. 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential22
Module Practice and QuizWhat did I learn in this module? (Cont.)Common IOS troubleshooting commands to troubleshoot IPv4 Static and default routesinclude: ping traceroute show ip route show ip interface brief show cdp neighbors detail 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential23
Module Objective: Troubleshoot static and default route configurations. Topic Title Topic Objective Packet Processing with Static Routes Explain how a router processes packets when a static route is configured. Troubleshoot IPv4 Static and Default Route Configuration Troubleshoot common static and default route configuration issues.
Teacher’s Book B LEVEL - English in school 6 Contents Prologue 8 Test paper answers 10 Practice Test 1 11 Module 1 11 Module 2 12 Module 3 15 Practice Test 2 16 Module 1 16 Module 2 17 Module 3 20 Practice Test 3 21 Module 1 21 Module 2 22 Module 3 25 Practice Test 4 26 Module 1 26 Module 2 27 Module 3 30 Practice Test 5 31 Module 1 31 Module .
Functional Testing · the health system · Trigger test messages · Troubleshoot Issues End-to-End Testing · between the health system, · Run test scenarios · Troubleshoot Issues · set up and workflows to end users Soft Go Live · · Turn on interface feeds · Troubleshoot Issues Go Live · Provide end user support · Troubleshoot Issues
WinDbg Commands . 0:000 k . Module!FunctionD Module!FunctionC 130 Module!FunctionB 220 Module!FunctionA 110 . User Stack for TID 102. Module!FunctionA Module!FunctionB Module!FunctionC Saves return address Module!FunctionA 110 Saves return address Module!FunctionB 220 Module!FunctionD Saves return address Module!FunctionC 130 Resumes from address
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Configure IP Default Static Routes Default Static Route (Cont.) IPv4 Default Static Route: The command syntax for an IPv4 default static route is similar to any other IPv4 static route, except that the network address is0.0.0.0and the subnet mask is0.0.0.0. The 0.0.0.0 0.0.0.0 in the route will match any network address.
Resume After a Suspend TCP Delayed-ACK Window Size Selects Incorrect Gateway Typical User Example Troubleshoot OGS Step 1. Clear the OGS Cache in Order to Force a Reevaluation . This document describes how to troubleshoot issues with Optimal Gateway Selection (OGS). OGS is a feature that ca
3M ª Metal-in Static Shielding Bag SCC 1000, Open Top and Ziptop . Static Shielding Bag SCC 1300 3M . 3M ª Metal-Out Static Shielding Bag SCC 1500, Open Top and Ziptop 3M Metal-Out Cushioned Static Shielding Bag 2120R Metal-in Shield Bags are intended to provide a static safe environment for electronic devices. Metal-in Shield Bags
Andreas M unch and Endre S uli Mathematical Institute, University of Oxford Andrew Wiles Building, Radcli e Observatory Quarter, Woodstock Road Oxford OX2 6GG, UK Barbara Wagner Weierstrass Institute Mohrenstraˇe 39 10117 Berlin, Germany and Technische Universit at Berlin, Institute of Mathematics Straˇe des 17. Juni 136 10623 Berlin, Germany (Communicated by Thomas P. Witelski) Abstract .
