Verifying an OSPF Configuration

To verify an OSPF configuration, perform these tasks:

Purpose

Verify that OSPF is running on a particular interface and that the interface is in the desired area.

Action

From the CLI, enter the show ospf interface command.

Sample Output

Intf                State     Area            DR ID           BDR ID       Nbrs
at-5/1/0.0          PtToPt   0.0.0.0         0.0.0.0         0.0.0.0         1
ge-2/3/0.0          DR       0.0.0.0         192.168.4.16    192.168.4.15    1
lo0.0               DR       0.0.0.0         192.168.4.16    0.0.0.0         0
so-0/0/0.0          Down     0.0.0.0         0.0.0.0         0.0.0.0         0
so-6/0/1.0          PtToPt   0.0.0.0         0.0.0.0         0.0.0.0         1
so-6/0/2.0          Down     0.0.0.0         0.0.0.0         0.0.0.0         0
so-6/0/3.0          PtToPt   0.0.0.0         0.0.0.0         0.0.0.0         1

What it Means

The output shows a list of the Services Router interfaces that are configured for OSPF. Verify the following information:

• Each interface on which OSPF is enabled is listed.
• Under Area, each interface shows the area for which it was configured.
• Under Intf and State, the Services Router loopback (lo0.0) interface and LAN interface that are linked to the OSPF network's designated router (DR) are identified.
• Under DR ID, the IP address of the OSPF network's designated router appears.
• Under State, each interface shows a state of PtToPt to indicate a point-to-point connection. If the state is Waiting, check the output again after several seconds. A state of Down indicates a problem.
• The designated router addresses always show a state of DR.

For more information about show ospf interface, see the JUNOS Protocols, Class of Service, and System Basics Command Reference.

Purpose

OSPF neighbors are interfaces that have an immediate adjacency. On a point-to-point connection between the Services Router and another router running OSPF, verify that each router has a single OSPF neighbor.

Action

From the CLI, enter the show ospf neighbor command.

Sample Output

 Address         Intf               State      ID              Pri  Dead
192.168.254.225  fxp3.0              2Way      10.250.240.32    128   36
192.168.254.230  fxp3.0              Full      10.250.240.8     128   38
192.168.254.229  fxp3.0              Full      10.250.240.35    128   33
10.1.1.129       fxp2.0              Full      10.250.240.12    128   37
10.1.1.131       fxp2.0              Full      10.250.240.11    128   38
10.1.2.1         fxp1.0              Full      10.250.240.9     128   32
10.1.2.81        fxp0.0              Full      10.250.240.10    128   33

What it Means

The output shows a list of the Services Router's OSPF neighbors and their addresses, interfaces, states, router IDs, priorities, and number of seconds allowed for inactivity (“dead” time). Verify the following information:

• Each interface that is immediately adjacent to the Services Router is listed.
• The Services Router's own loopback address and the loopback addresses of any routers with which the Services Router has an immediate adjacency are listed.
• Under State, each neighbor shows a state of Full. Because full OSPF connectivity is established over a series of packet exchanges between clients, the OSPF link might take several seconds to establish. During that time, the state might be displayed as Attempt, Init, or 2way, depending on the stage of negotiation.

  If, after 30 seconds, the state is not Full, the OSPF configuration between the neighbors is not functioning correctly.

For more information about show ospf neighbor, see the JUNOS Protocols, Class of Service, and System Basics Command Reference.

Purpose

Verify that the OSPF routing table has entries for the following:

• Each subnetwork reachable through an OSPF link
• Each loopback address reachable on the network

For example, Figure 50 shows a sample network with an OSPF topology.

In this topology, OSPF is being run on all interfaces. Each segment in the network is identified by an address with a /24 prefix, with interfaces on either end of the segment being identified by unique IP addresses.

Action

From the CLI, enter the show ospf route command.

Sample Output

Prefix               Path   Route       NH   Metric  NextHop       Nexthop      
                     Type   Type        Type         Interface     addr/label
10.10.10.1/24        Intra  Network     IP   1       fe-0/0/2.0    10.0.21.1
10.10.10.2/24        Intra  Network     IP   1       fe-0/0/2.0    10.0.21.1
10.10.10.4/24        Intra  Network     IP   1       fe-0/0/1.0    10.0.13.1
10.10.10.5/24        Intra  Network     IP   1       fe-0/0/2.0    10.0.21.1
10.10.10.6/24        Intra  Network     IP   1       fe-0/0/1.0    10.0.13.1
10.10.10.10/24       Intra  Network     IP   1       fe-0/0/2.0    10.0.21.1
10.10.10.11/24       Intra  Network     IP   1       fe-0/0/1.0    10.0.13.1
10.10.10.13/24       Intra  Network     IP   1       fe-0/0/1.0
10.10.10.16/24       Intra  Network     IP   1       fe-0/0/1.0    10.0.13.1
10.10.10.19/24       Intra  Network     IP   1       fe-0/0/1.0    10.0.13.1
10.10.10.20/24       Intra  Network     IP   1       fe-0/0/2.0    10.0.21.1
10.10.10.21/24       Intra  Network     IP   1       fe-0/0/2.0
192.168.5.1          Intra  Router      IP   1       fe-0/0/2.0    10.0.21.1
192.168.5.2          Intra  Router      IP   1       lo0    
192.168.5.3          Intra  Router      IP   1       fe-0/0/1.0    10.0.13.1
192.168.5.4          Intra  Router      IP   1       fe-0/0/1.0    10.0.13.1
192.168.5.5          Intra  Router      IP   1       fe-0/0/1.0    10.0.13.1
192.168.5.6          Intra  Router      IP   1       fe-0/0/2.0    10.0.21.1
192.168.5.7          Intra  Router      IP   1       fe-0/0/2.0    10.0.21.1
192.168.5.8          Intra  Router      IP   1       fe-0/0/2.0    10.0.21.1
192.168.5.9          Intra  Router      IP   1       fe-0/0/1.0    10.0.13.1

What it Means

The output lists each route, sorted by IP address. Routes are shown with a route type of Network, and loopback addresses are shown with a route type of Router.

For the example shown in Figure 50, verify that the OSPF routing table has 21 entries, one for each network segment and one for each router's loopback address.

For more information about show ospf route, see the JUNOS Protocols, Class of Service, and System Basics Command Reference.

Purpose

By using the traceroute tool on each loopback address in the network, verify that all hosts in the network are reachable from each Services Router.

Action

For each Services Router in the OSPF network:

1. In the J-Web interface, select Diagnose>Traceroute.
2. In the Host Name box, type the name of a host for which you want to verify reachability from the Services Router.
3. Click Start. Output appears on a separate page.

Sample Output

1 172.17.40.254 (172.17.40.254) 0.362 ms 0.284 ms 0.251 ms 
2 routera-fxp0.englab.mycompany.net (192.168.71.246) 0.251 ms 0.235 ms 0.200 ms 

What it Means

Each numbered row in the output indicates a router (“hop”) in the path to the host. The three time increments indicate the round-trip time (RTT) between the Services Router and the hop, for each traceroute packet. To ensure that the OSPF network is healthy, verify the following information:

• The final hop in the list is the host you want to reach.
• The number of expected hops to the host matches the number of hops in the traceroute output. The appearance of more hops than expected in the output indicates that a network segment is likely not reachable. In this case, verify the routes with the show ospf route command.

For information about ospf routeshow , see Verifying the Number of OSPF Routes.

For information about the traceroute command and its output, see the JUNOS Protocols, Class of Service, and System Basics Command Reference.