Error on Listen function: The requested TCP/IP port is in use on this system.
This message could indicate one of the following problems:

• UNIX® systems. You have failed to assign different IP addresses to each partition on a Domino partitioned server, or you have failed to follow the port mapping setup instructions properly, and you attempt to start the additional partition. You may need to stop the server currently running, so that the new server you are setting up can finish accessing the setup server for its copy of the Domino Directory.

  Note Failing to configure partitions properly on Microsoft® Windows® systems does not generate an error on startup, but will generate operational problems.

• Windows 2000 and XP systems. It is possible for an application or system service to be assigned an ephemeral port number as its local port number that conflicts with the Domino listening port. Restart the system so that the process using TCP port number 1352 can release it.

  When a system running TCP/IP makes each outbound connection, the TCP software automatically selects a local port number and assigns it to the connection. This is required in the TCP architecture so that the server can return packets to the client. This same port number cannot be used by any other outbound or listening socket until it is freed. Port numbers in the range 1 - 1024 are called reserved ports because they are reserved for well-known system services. The TCP software never uses reserved ports when it must select a client-side port number at random. Rather, it selects at random a number from a range above 1024 called the ephemeral port range. The Internet authority uses the low-end range above 1024 to assign port numbers to registered applications such as Lotus Notes/Domino's NRPC services, which use 1352. Microsoft uses the ephemeral port range of 1024 - 5000. Therefore, when a server on a Windows system makes an outbound connection, the ephemeral port number chosen might be 1352. When this happens and Domino is started, the NRPC port fails to bind. Often, on startup, servers on Windows systems make outbound connections to the NetBIOS session service well-known port and keep these connections active until the system is restarted. This is the cause of the problem.

  Note Most UNIX systems use an ephemeral port range that is at the top-end of the range of ports, such as 45000 - 65000, so that there is not likely to be a conflict between the ephemeral port number chosen and registered port numbers.

  To determine if this is the cause of the problem, run Netstat -n -a. If what you see is similar to one of the following examples, the system is using port number 1352 and the Domino server cannot start. To solve this problem, restart the system.

  Example 1: Netstat -n -a output of the Domino server active on the local system using port 1352 as a server

  Proto  Local Address          Foreign Address        State

  TCP    10.20.4.137:1352       0.0.0.0:0              LISTENING

Example 2: Netstat -n -a output of the local system accessing an external system using port 1352 ephemerally

Proto  Local Address          Foreign Address        State

TCP    10.20.4.137:1352       10.30.10.1:139         ESTABLISHED

To prevent future ephemeral bind conflicts on Microsoft® Windows® systems, use the following instructions to add a registry value that forces TCP to skip port 1352 when it selects an ephemeral port number:

Run Regedt32 (not Regedit -- Regedit does not support the data type required for the value) and enter the following:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Value Name: ReservedPorts

Data Type: REG_MULTI_SZ

Value: 1352-1352

Tip To protect additional ports, you can enter a range (such as 1025 - 1050) or multiple ranges separated by spaces.

Note In Windows 2000 and XP, Netstat might report an additional line showing the local and remote ports and addresses in the established state, or a second line showing the client-side port in the listening state. This is only a different method of reporting listening ports -- not a network bug.

As a temporary solution or if you can't make any alterations to the system or TCP/IP stack, you can limit the number of NRPC sessions the server will support concurrently, but there will be a performance cost for doing so. To limit the number of concurrent NRPC sessions, do one of the following:

• Edit the portname_MaxSessions setting in the NOTES.INI file to limit the number of sessions that can run on this port.
• Edit the Server_MaxSessions setting in the NOTES.INI file to limit the total number of active sessions the server can have.

The remote TCP/IP host is not running the Domino server, or the server is busy.
The server is currently not running, or the server can't accept another TCP/IP connection or Domain session. Start the server, or verify that it is running. Check the server to determine if its workload is unacceptably heavy.

The TCP/IP protocol stack reported that it ran out of memory. Consult your network documentation to increase configured memory, or reduce Notes connections by limiting clients (see SERVER_MAXSESSIONS parameter in Notes Admin Guide).
This error can occur when your server system's resources are not correctly sized for the number of inbound and outbound connections or when events push the server into resource starvation.

• If system memory appears to be low, increase it.
• If you are using Microsoft® Windows® NT, you may be encountering a page file limit. Both IBM® Lotus® Domino™ and the TCP/IP stack use shared memory. If the page file is not large enough or the number of pages exceeds what the operating system can provide, this error appears. Upgrade the operating system to Windows 2000 with Service Pack 2.
• If inbound client and server connections or the server's own outbound connections seem to be experiencing network stability problems, verify the health of the network by using Netstat with the -n switch (to disable reverse DNS lookups) and output the listing to a file. Import the listing to a spreadsheet and count the total number of connections. Then break the connections down by their state (Established, Time_Wait, Close_Wait, Fin_Waitn). You should be able to support more than 2,000 concurrent connections. If not, review your operating system and TCP/IP stack settings with the operating system and TCP/IP stack vendor. If you have a large number of Close_Wait sessions, you may have network-level problems. If you have a buildup of Time_Wait sessions with HTTP services, review your TCP/IP stack's settings to see if the stack offers a setting to time out Time_Wait sessions sooner.

• Edit the Port_MaxSessions setting in the NOTES.INI file to limit the number of sessions that can run on this port.
• Edit the Server_MaxSessions setting in the NOTES.INI file to limit the total number of active sessions the server can have.

Unexpected TCP error. See the Notes log file on this system for error code.
Look in the log file to see the reported error code or codes. KnowledgeBase lists many of the error codes. If you find an error code that isn't in KnowledgeBase, report it to Lotus Support Services.

See also

Troubleshooting TCP/IP problems for NRPC

Glossary