Viewing Routes Learned by OSPF
Problem
You want to check the routes that are being generated by the Dijkstra SPF calculation to make sure that the router is learning the expected routes.
Solution
Use the show ospf route command to see the contents of the OSPF routing table:
aviva@RouterG> show ospf route Prefix Path Route NH Metric NextHop Nexthop Type Type Type Interface addr/label 192.168.17.1 Intra Router IP 1 fe-1/0/1.0 10.0.0.2 192.168.18.1 Intra Router IP 1 fe-0/0/1.0 10.0.1.1 10.0.0.0/24 Intra Network IP 1 fe-1/0/1.0 10.0.1.0/24 Intra Network IP 1 fe-0/0/1.0 10.0.2.0/24 Intra Network IP 2 fe-0/0/1.0 10.0.1.1 fe-1/0/1.0 10.0.0.2 192.168.17.1/32 Intra Network IP 1 fe-1/0/1.0 10.0.0.2 192.168.18.1/32 Intra Network IP 1 fe-0/0/1.0 10.0.1.1
Discussion
OSPF routers perform an SPF calculation to determine the best route to a destination and places these routes in its routing table. The show ospf route command displays whats in the OSPF routing table. The Prefix column shows the destinations on the network, and you also see the interface used to reach the next hop toward the destination and the IP address of that next hop.
You can find out which routes the router has learned from OSPF by checking the unicast routing table:
aviva@RouterG> show route table inet.0 inet.0: 11 destinations, 11 routes (11 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 10.0.0.0/24 *[Direct/0] 3d 01:42:24 > via fe-1/0/1.0 10.0.0.1/32 *[Local/0] 3d 01:42:24 Local via fe-1/0/1.0 10.0.1.0/24 *[Direct/0] 3d 01:42:24 > via fe-0/0/1.0 10.0.1.2/32 *[Local/0] 3d 01:42:24 Local via fe-0/0/1.0 10.0.2.0/24 *[OSPF/10] 00:18:28, metric 2 to 10.0.1.1 via fe-0/0/1.0 > to 10.0.0.2 via fe-1/0/1.0 10.0.16.0/24 *[Direct/0] 3d 01:42:24 > via fe-1/0/0.0 10.0.16.2/32 *[Local/0] 3d 01:42:24 Local via fe-1/0/0.0 192.168.17.1/32 *[OSPF/10] 00:18:28, metric 1 > to 10.0.0.2 via fe-1/0/1.0 192.168.18.1/32 *[OSPF/10] 00:18:28, metric 1 > to 10.0.1.1 via fe-0/0/1.0 192.168.19.1/32 *[Direct/0] 3d 01:40:56 > via lo0.0 224.0.0.5/32 *[OSPF/10] 2d 20:52:32, metric 1 MultiRecv
The route entries starting with [ OSPF/10] are those learned from OSPF. The router has learned four routes from OSPF:
- 192.168.17.1/32 and 192.168.18.1./32 are router loopback addresses that are the two OSPF neighbors we saw in the OSPF routing table.
- 10.0.2.0/24 is a subnetwork that is the subnet between our two neighbors (which we also saw in the OSPF database).
- 224.0.0.5/32 is the OSPF multicast address.
The routes to the two loopback addresses show up in the routing table because the router ID is configured on the routers lo0 addresses, not with the set routing-options router-id command.
The value of 10 in the brackets is the JUNOS default value for the OSPF administrative distance, also called the routing preference, which is used to select what route is installed in the forwarding table when several protocols calculate routes to the same destination. A preference of 10 is the default for internal OSPF routes, which are those within the domain. The preference value for routes outside the domain that OSPF advertises is 150. You can change the preference value by configuring the preference statement for the OSPF area. The numbers following the brackets show how long the routing table has known about the route. The metric value (either 1 or 2) is the cost to this address. Understanding the routing table is discussed more in Recipe 9.1.
You might find it strange that a multicast address, 224.0.0.5/32, is present in the inet.0 routing table, which is the unicast routing table. This is simply a result of a JUNOS design decision. Instead of establishing a separate routing table for the few multicast routes used by routing protocols for receiving protocol packets, which are well-known addresses, the JUNOS software places these routes in the unicast routing table.
You can also see just the routes learned by OSPF:
aviva@RouterG> show route protocol ospf table inet.0 inet.0: 14 destinations, 14 routes (14 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 10.0.2.0/24 *[OSPF/10] 00:00:26, metric 2 to 10.0.1.1 via fe-0/0/1.0 > to 10.0.0.2 via fe-1/0/1.0 192.168.17.1/32 *[OSPF/10] 00:00:26, metric 1 > to 10.0.0.2 via fe-1/0/1.0 192.168.18.1/32 *[OSPF/10] 00:00:31, metric 1 > to 10.0.1.1 via fe-0/0/1.0 224.0.0.5/32 *[OSPF/10] 00:00:42, metric 1 MultiRecv
Router Configuration and File Management
- Introduction
- Configuring the Router for the First Time
- Configuring the Router from the CLI
- Getting Exclusive Access to Configure the Router
- Displaying the Commands to Recreate a Configuration
- Including Comments in the Configuration
- Checking the Syntax of the Configuration
- Activating the Router Configuration
- Debugging a Failed Commit
- Exiting Configuration Mode
- Keeping a Record of Configuration Changes
- Determining What Changes You Have Made to the Configuration
- Configuring the Router by Copying a File from a Server
- Configuring the Router by Copying Text from a Terminal Window
- Backing Up the Routers Configuration
- Scheduling the Activation of a Configuration
- Provisionally Activating a Configuration
- Loading a Previous Router Configuration
- Creating an Emergency Rescue Configuration
- Backing Up Filesystems on M-Series and T-Series Routers
- Backing Up Filesystems on J-Series Routers
- Restoring a Backed-Up Filesystem
- Installing a Different Software Release on M-Series and T-Series Routers
- Installing a Different Software Release on J-Series Routers
- Creating an Emergency Boot Disk
- Gathering Software Version Information
- Gathering Hardware Inventory Information
- Finding Out How Long the Router Has Been Up
- Gathering Information Before Contacting Support
- Managing Routers with Similar Configurations
- Managing Redundant Routing Engines
- Using the Second Routing Engine to Upgrade to a New Software Version
Basic Router Security and Access Control
- Basic Router Security and Access Control
- Introduction
- Allowing Access to the Router
- Controlling Root Authentication
- Logging In to the Routers Console
- Setting the Login Authentication Methods
- Setting Up Login Accounts on the Router
- Changing the Format of Plain-Text Passwords
- Changing the Plain-Text Password Encryption Method
- Creating a Login Account for Remote Authentication
- Creating a Group Login Account
- Customizing Account Privileges
- Creating a Privilege Class that Hides Encrypted Passwords
- Setting Up RADIUS User Authentication
- Setting Up TACACS+ User Authentication
- Restricting Inbound SSH and Telnet Access
- Setting the Source Address for Telnet Connections
- Creating a Login Banner
- Finding Out Who Is Logged In to the Router
- Logging Out of the Router
- Forcibly Logging a User Out
IPSec
- IPSec
- Introduction
- Configuring IPSec
- Configuring IPSec Dynamic SAs
- Creating IPSec Dynamic SAs on J-Series Routers or Routers with AS PICs
- Using Digital Certificates to Create Dynamic IPSec SAs
SNMP
- SNMP
- Introduction
- Configuring SNMP
- Setting Router Information for the MIB-II System Group
- Setting Up SNMP Traps
- Controlling SNMP Access to the Router
- Using a Firewall Filter to Protect SNMP Access
- Controlling Access to Router MIBs
- Extracting Software Inventory Information with SNMP
- Extracting Hardware Inventory Information with SNMP
- Collecting Router Operational Information with SNMP
- Logging SNMP Access to the Router
- Logging Enterprise-Specific Traps
- Using RMON Traps to Monitor the Routers Temperature
- Configuring SNMPv3
- Tracking Router Configuration Changes
- Setting Up SNMPv3 Traps
Logging
- Logging
- Introduction
- Turning On Logging
- Limiting the Messages Collected
- Including the Facility and Severity in Messages
- Changing the Size of a Logging File
- Clearing the Routers Logfiles
- Sending Log Messages to Your Screen
- Sending Logging Messages to a Log Server
- Saving Logging Messages to the Other Routing Engine
- Turning Off Logging
- Turning On Basic Tracing
- Monitoring Interface Traffic
NTP
- NTP
- Introduction
- Setting the Date and Time on the Router Manually
- Setting the Time Zone
- Synchronizing Time When the Router Boots
- Synchronizing Time Periodically
- Authenticating NTP
- Checking NTP Status
Router Interfaces
- Router Interfaces
- Introduction
- Viewing Interface Status
- Viewing Traffic Statistics on an Interface
- Setting an IP Address for the Router
- Setting the Routers Source Address
- Configuring an IPv4 Address on an Interface
- Configuring an IPv6 Address on an Interface
- Configuring an ISO Address on an Interface
- Creating an MPLS Protocol Family on a Logical Interface
- Configuring an Interface Description
- Choosing Primary and Preferred Interface Addresses
- Using the Management Interface
- Finding Out What IP Addresses Are Used on the Router
- Configuring Ethernet Interfaces
- Using VRRP on Ethernet Interfaces
- Connecting to an Ethernet Switch
- Configuring T1 Interfaces
- Performing a Loopback Test on a T1 Interface
- Setting Up a BERT Test on a T1 Interface
- Configuring Frame Relay on a T1 Interface
- Configuring a SONET Interface
- Using APS to Protect Against SONET Circuit Failures
- Configuring an ATM Interface
- Dealing with Nonconfigurable Interfaces
- Configuring Interfaces Before the PICs Are Installed
IP Routing
- IP Routing
- Introduction
- Viewing the Routes in the Routing Table
- Viewing Routes to a Particular Prefix
- Viewing Routes Learned from a Specific Protocol
- Displaying the Routes in the Forwarding Table
- Creating Static Routes
- Blackholing Routes
- Filtering Traffic Using Unicast Reverse-Path Forwarding
- Aggregating Routes
- Load-Balancing Traffic Flows
- Adding Martian Addresses
- Changing Route Preferences to Migrate to Another IGP
- Configuring Routing Protocols to Restart Without Losing Adjacencies
Routing Policy and Firewall Filters
- Routing Policy and Firewall Filters
- Introduction
- Creating a Simple Routing Policy
- Changing a Routes Routing Information
- Filtering Routes by IP Address
- Filtering Long Prefixes
- Filtering Unallocated Prefix Blocks
- Creating a Chain of Routing Policies
- Making Sure a Routing Policy Is Functioning Properly
- Creating a Simple Firewall Filter that Matches Packet Contents
- Creating a Firewall Filter that Negates a Match
- Reordering Firewall Terms
- Filtering Traffic Transiting the Router
- Using a Firewall Filter to Count Traffic on an Interface
- Logging the Traffic on an Interface
- Limiting Traffic on an Interface
- Protecting the Local Routing Engine
- Rate-Limiting Traffic Flow to the Routing Engine
- Using Counters to Determine Whether a Router Is Under Attack
RIP
- RIP
- Introduction
- Configuring RIP
- Having RIP Advertise Its Routes
- Configuring RIP for IPv6
- Enabling RIP Authentication
- Routing RIP Traffic over Faster Interfaces
- Sending Version 1 Update Messages
- Tracing RIP Protocol Traffic
IS-IS
- IS-IS
- Introduction
- Configuring IS-IS
- Viewing the IS-IS Link-State Database
- Viewing Routes Learned by IS-IS
- Configuring IS-IS for IPv6
- Configuring a Level 1Only Router
- Controlling DIS Election
- Enabling IS-IS Authentication
- Redistributing Static Routes into IS-IS
- Leaking IS-IS Level 2 Routes into Level 1
- Adjusting IS-IS Link Costs
- Improving IS-IS Convergence Times
- Moving IS-IS Traffic off a Router
- Disabling IS-IS on an Interface
- Tracing IS-IS Protocol Traffic
OSPF
- Introduction
- Configuring OSPF
- Viewing Routes Learned by OSPF
- Viewing the OSPF Link-State Database
- Configuring OSPF for IPv6
- Configuring a Multiarea OSPF Network
- Setting Up Stub Areas
- Creating a Not-So-Stubby Area
- Summarizing Routes in OSPF
- Enabling OSPF Authentication
- Redistributing Static Routes into OSPF
- Adjusting OSPF Link Costs
- Improving OSPF Convergence Times
- Moving OSPF Traffic off a Router
- Disabling OSPF on an Interface
- Tracing OSPF Protocol Traffic
BGP
- Introduction
- Configuring a BGP Session Between Routers in Two ASs
- Configuring BGP on Routers Within an AS
- Diagnosing TCP Session Problems
- Adjusting the Next-Hop Attribute
- Adjusting Local Preference Values
- Removing Private AS Numbers from the AS Path
- Prepending AS Numbers to the AS Path
- Filtering BGP Routes Based on AS Paths
- Restricting the Number of Routes Advertised to a BGP Peer
- Authenticating BGP Peers
- Setting Up Route Reflectors
- Mitigating Route Instabilities with Route Flap Damping
- Adding a BGP Community to Routes
- Load-Balancing BGP Traffic
- Tracing BGP Protocol Traffic
MPLS
- Introduction
- Configuring LSPs Using LDP as the Signaling Protocol
- Viewing Information and LDP-Signaled LSPs in the Routing Tables
- Verifying that an LDP-Signaled LSP Is Carrying Traffic
- Enabling LDP Authentication
- Tracing LDP Operations
- Setting Up RSVP-Signaled LSPs
- Viewing Information About RSVP-Signaled LSPs in the Routing Tables
- Verifying Packet Labels
- Verifying that the RSVP-Signaled LSP Is Carrying Traffic
- Configuring RSVP Authentication
- Protecting an LSPs Path
- Using Fast Reroute to Reduce Packet Loss Following a Link Failure
- Automatically Allocating Bandwidth
- Prioritizing LSPs
- Allowing IGP Traffic to Use an LSP
- Installing LSPs into the Unicast Routing Table
- Tracing RSVP Operations
VPNs
- Introduction
- Setting Up a Simple Layer 3 VPN
- Viewing the VPN Routing Tables
- Adding a VPN for a Second Customer
IP Multicast
- Introduction
- Configuring PIM-SM
- Manually Establishing a PIM-SM RP
- Using Auto-RP to Dynamically Map RPs
- Setting Up a PIM-SM Bootstrap Router
- Filtering PIM-SM Bootstrap Messages
- Configuring Multiple RPs in a PIM-SM Domain with Anycast RP
- Configuring Multiple RPs in a PIM-SM Domain Anycast PIM
- Limiting the Group Ranges an RP Services
- Viewing Multicast Routes
- Checking the Groups for Which a PIM-SM Router Maintains Join State
- Manually Configuring IGMP
- Using SSM
- Connecting PIM-SM Domains Using MSDP and MBGP
- Configuring PIM-DM
- Tracing PIM Packets
Junos Cookbook (Cookbooks (OReilly))
ISBN: 0596100140
EAN: 2147483647
EAN: 2147483647
Year: 2007
Pages: 290
Pages: 290
Authors: Aviva Garrett
