Event ID 41031 — RRAS IGMP Multicast Group Joining

Applies To: Windows Server 2008

Internet Group Management Protocol (IGMP) maintains host group membership on a local subnet. Hosts use IGMP to communicate multicast group membership requests with their local multicast router. Routers receive the group membership requests and periodically send queries to determine which host groups are active or inactive on the local subnet. This protocol is required to support Level 2 multicasting. Internet Protocol version 6 (IPv6) uses Multicast Listener Discovery (MLD) instead of IGMP to manage group membership.

Event Details

Resolve

Configure or reinstall the IGMP interface, check memory status, restart Routing and Remote Access service

Possible resolutions:

• Delete and reinstall the IGMP interface. For more information, see the "Remove and Reinstall IGMP" section.
• Check the configuration settings on the interface. For more information, see the "Configure IGMP" section.
• This computer might be low on memory. For more information, see the "Check memory usage on the server" section.
• Stop and restart the Routing and Remote Access service. For more information, see the "Restart the remote access service" section.
• Restart the computer.

To perform these procedures, you must have membership in Administrators, or you must have been delegated the appropriate authority.

Remove and reinstall IGMP

To remove and reinstall IGMP:

1. Open Routing and Remote Access. Click Start, click Run, type rrasmgmt.msc, and then press ENTER.
2. In the console tree, expand IPv4, right-click IGMP,** **and then click Delete.
3. Click Yes in the confirmation dialog box.
4. Under IPv4, right-click General, and then click New Routing Protocol.
5. Click IGMP Router and Proxy, and then click OK.
6. Under IPv4, right-click IGMP, and then click New Interface.
7. Click the interface for IGMP, and then click OK.
8. Modify the settings in the IGMP properties dialog box, and then click OK.

Configure IGMP

To configure IGMP:

1. Open Routing and Remote Access. Click Start, click Run, type rrasmgmt.msc, and then press ENTER.
2. In the console tree, expand IPv4, and then click IGMP.
3. In the details pane, right-click the interface you want to configure, and then click Properties.
4. Check the settings on the General and Router tabs.

Check memory usage on the server

To check memory usage on the remote access server:

1. On the remote access server, click Start, click Run, type taskmgr, and then click OK.
2. In the Windows Task Manager dialog box, click the Performance tab.
3. Under Physical Memory, check the emote access server's memory usage.
4. If necessary, free up available memory by ending non-essential applications or processes.

Restart the remote access service

To restart the remote access service:

1. Open Routing and Remote Access. Click Start, click Run, type rrasmgmt.msc, and then press ENTER.
2. By default, the local computer is listed as a server. To add another server, in the console tree, right-click Server Status, and then click Add Server. In the Add Server dialog box, click the appropriate option, and then click OK.
3. In the console tree, right-click the server you want to restart, click All Tasks, and then click Restart.

Verify

You can verify multicast routing configuration with the mrinfo command. You can use the configuration information to aid in the troubleshooting of multicast forwarding and routing problems.

The mrinfo command queries a specified multicast router with an Internet Group Management Protocol (IGMP) message. The response to the query contains a version number, the list of interfaces and the neighbors on each interface, metrics, Time to Live (TTL) thresholds, and flags. The syntax of the mrinfo command is:

mrinfo [-n] [ -i address ] [ -r retry_count ] [ -t timeout_count ] multicast_router

• The -n option displays IP addresses in numeric format.
• The -i option specifies the IP address of the interface from which you want to send the mrinfo query. By default, the interface from which to send the mrinfo query is determined by the IP routing table.
• The -r option specifies the neighbor query retry limit. The default value is 3.
• The -t option specifies how long, in seconds, mrinfo waits for a neighbor query reply. The default value is 4.

The following is an example of the mrinfo command:

C:\>mrinfo 10.1.0.1

10.1.0.1(test1.microsoft.com) [version 18.55,mtrace,snmp]:

10.1.0.1 -> 0.0.0.0 (local) [1/0/querier/leaf]

10.2.0.1 -> 10.2.0.2 (test2.microsoft.com) [1/0]

10.2.0.1 -> 10.2.0.3 (test3.microsoft.com) [1/0]

10.3.0.1 -> 0.0.0.0 (local) [1/0/querier/leaf]

In the preceding example, mrinfo is run against the multicast router at 10.1.0.1. The first line shows the multicast router configuration: version number (for servers running Routing and Remote Access, the version number reflects the build number of the operating system) and flags (mtrace and snmp supported).

Each additional line displays the interfaces on the multicast router and the neighbors on each interface. Interfaces 10.1.0.1 and 10.3.0.1 have no neighbors. Interface 10.2.0.1 has two neighbors, 10.2.0.2 and 10.2.0.3. For each line, mrinfo displays the interface and neighbor, the domain name for the neighbor, the multicast routing metric, the TTL threshold, and flags indicating its role on the network, such as the IGMP querier of the network (querier) or whether it has no neighbors (leaf).

Related Management Information

RRAS IGMP Multicast Group Joining

Routing and Remote Access Service Infrastructure