Event IDs 21249 and 21248 are logged in the application event log on a computer that is running Microsoft Operations Manager (883335)

RESOLUTION

1. On the computer that has the MOM 2005 agent installed, click Start, click Run, type cmd, and then click OK
2. At the command prompt, type ping MOMServerName, where MOMServerName is the name of the computer that is the listed in the Computer: field in the event warning message that is described in the "Symptoms" section. Note the IP address that is returned.
3. If the ping response is successful, you must now verify that the IP address that is returned is the actual IP address of the MOM server by using the ping command with the -a switch. To do this, follow these steps:
   1. At the command prompt, type ping -a IPAddress, where IPAddress is the IP address from step 2. An example is ping -a 10.10.1.10.
   2. The output of ping -a IPAddress must match the MOM server name. If the IP address matches the MOM server name, go to step 8. If the output does not match the MOM server name, go to the next step.
4. If the output of the ping -a command does not match the name of the MOM server, the MOM agent cannot resolve the MOM server name to the correct IP address. This problem may for any one of the following reasons:
   • The local DNS client cache has stale DNS entries for the IP address. For example, the IP of the MOM server changes, but the MOM agent still has a cached name resolution entry for the old IP. This old IP is now used by another computer. Because of this, the ping -a IP address resolves to a computer name other than the MOM server.
   • The MOM agent computer contains a Hosts file in the %Windir%\System32\Drivers\Etc folder that contains an entry that adjusts the name resolution table for the IP address to the wrong computer name.
   • The DNS or WINS server that the MOM agent computer uses for name resolution contains a stale or incorrect entry.
   The remaining steps can help determine whether the name resolution problem is local to the MOM agent computer or if it exists in the name resolution service, and may affect other MOM agent computers.
   
   Note Two examples of such name resolution services are DNS and WINS.
5. Determine whether the name resolution problem is local to the MOM agent computer or if there is a problem with the name resolution service that the MOM agent computer uses. To do this, follow these steps:
   1. On the computer that is running the MOM agent, click Start, click Run, type cmd, and then click OK.
   2. At the command prompt, type the following commands. Press enter after you type each command.
      • Nbtstat -RR
      • Ipconfig /flushdns
   3. Remove any static entries for MOM server IP Address or MOM server name in the Hosts file that is contained in the %Windir%\System32\Drivers\Etc folder on the MOM agent computer. You can change the Hosts file with Notepad.
   4. Repeat step 3. The ping -a command is successful if the output matches the MOM server name. If it is successful, the local DNS cache on the MOM agent computer was at fault. Go to step 8. If the ping -a is unsuccessful, the MOM agent is still receiving incorrect name resolution information and you must go to step 6.
6. If the MOM agent computer still cannot resolve the correct IP address to the MOM server computer name, you must verify the name resolution services. To do this, follow these steps.
   Note You must have access to the name resolution server to perform all the following steps.
   1. On the MOM agent computer, click Start, click Run, type cmd, and then click OK.
   2. At the command prompt, type the following to see a list of Primary and Secondary DNS servers and primary and secondary WINS servers:

      ipconfig /all

   3. If you are using WINS for name resolution log on to the WINS server, follow these steps:
      1. Click Start, point Programs, point to Administrative Tools, and then click WINS.
      2. In the WINS snap-in, expand the WINS server name, right-click Active Registrations, and then click Find by Name.
      3. In the Find by name dialog box, type the name of the MOM server, and then click Find Now.
      4. Verify that the WINS entry for the MOM server points to the correct IP address. If the WINS record is incorrect, you can use WINS Help to resolve the problem. To access WINS Help, click the Help icon on the WINS menu bar.
      5. When you have resolved the name resolution, you must force WINS replication, and then repeat step 5.
7. If you are using DNS for name resolution, log on to the DNS server, and then follow these steps:
   1. Click Start, point to Programs, point to Administrative Tools, and then click DNS.
   2. In the DNS snap-in, expand the DNS server name, expand Forward Lookup Zones, and then click the zone name that contains the DNS entry for the MOM server.
   3. In the right pane of the DNS snap-in, make sure that the MOM server name points to the correct IP address. If the DNS record is incorrect, you can use DNS Help to resolve the problem. To access DNS Help, click the Help icon on the DNS menu bar.
   4. When you have resolved the name resolution problem, repeat step 5.
8. If you have confirmed that the MOM agent can resolve the IP address and the MOM server name correctly, and the problem still exists, you must verify that the MOM agent service is communicating correctly with the MOM server by using telnet to connect to port 1270 on the MOM server. To do this, follow these steps.
   
   Note The TCP port can be configured by using the MOM Administrative console. The value for the port can be found in Global Settings, under Communications.
   1. On the MOM agent computer, click Start, click Run, type cmd, and then click OK.
   2. At the command prompt, type the following: telnet IPAddress 1270, where IPAddress is the IP address of the computer that is running MOM.
   3. If the connection is successful, a blank command line window appears. This shows that the port that the MOM agent requires is open and listening on the computer that is running MOM.
   4. If the telnet command fails, the following response is returned:
      Connecting To 10.10.1.10...Could not open connection to the host on port 1270: Connect failed.
      In this case, you must verify the following:
      • That there are no IPSec policies that prevent communication.
      • That there are no local IPSec filters configured on any network adapters that prevent communication on port 1270 UDP and TCP.
      • There are no Access Control List (ACL) entries on the firewall, on the router, or on the Switch that prevent communication between the MOM agent and the MOM server.
        To find which ports must be opened for communication between the MOM agent and the MOM server, see the Microsoft Operations Manager 2005 Security Guide. To view the Microsoft Operations Manager 2005 Security Guide, visit the following Microsoft Web site:

        http://www.microsoft.com/technet/prodtechnol/mom/MOM2005/Library/3e039637-4639-46f7-9f5f-518e0c04795e.mspx

9. If you have confirmed that the MOM agent can resolve the name of the MOM server and that the MOM server that is listening on port 1270, but the problem still exists, contact Microsoft Product Support (PSS).