Managing Server Connections

This section explains how to enable and disable access to the server and how to monitor and solve common connection problems.


Disabling and Enabling Logins

If you need to make repairs to the server, use the DISABLE LOGIN command to prevent users from logging in.

NOTE:  This does not affect users who are already logged in to the network.

To reenable logins, or to enable a SUPERVISOR account when it has been locked by the intruder detection function, use ENABLE LOGIN.

For more information about these commands, see DISABLE LOGIN and ENABLE LOGIN in Utilities Reference.

For more information about the intruder detection function, see Table 7 and Table 9 in Chapter 1.


Clearing a Workstation Connection

You can use either the MONITOR utility or the CLEAR STATION command to clear a connection, as described in the following sections.

Use either of these procedures to clear a workstation connection when the workstation has crashed and left open files on the server.

NOTE:  If you clear the connection while the workstation is in the middle of a transaction or a file update, the files may be saved with incorrect data.


Using MONITOR to Clear the Connection


Procedure

  1. At the server console prompt, type

    LOAD MONITOR <Enter>

    2.

  2. Select Connection Information from the Available Options menu.

    A list of active connections appears.

    3.

  3. (Optional) To view files that are open for a workstation, highlight the connection and press <Enter>.

    After viewing files, press <Esc> to go back to the Connection Information screen.

    4.

  4. Clear one or more connections, as follows:

    • To clear one connection, highlight the connection and press <Delete>. At the Clear Connection? prompt, select Yes.
      •
    • To delete multiple connections, highlight each connection and press <F5> to mark it. Then press <Delete>. At the Clear Connection? prompt, select Yes.
      •
    • To clear all unused (not logged in) connections, press <F6>.
      •

    Deleted connections are no longer listed on the Connection Information screen.

    5.

Using the CLEAR STATION Command to Clear the Connection


Prerequisites


Procedure

  1. At the server console prompt, type

    CLEAR STATION n

    or

    CLEAR STATION ALL <Enter>

    Replace n with the connection number of the workstation, or use the ALL parameter to clear all connections.

    2.

Additional Information

For more information about See

Connection numbers

Connection number in Concepts

Using the CLEAR STATION command

CLEAR STATION in Utilities Reference

Using the MONITOR utility

MONITOR in Utilities Reference

Monitoring Workstation Connections

Use this procedure for early warning that a workstation connection has become inactive. This procedure changes the SET watchdog parameters, which a server sends to a workstation to determine if the workstation connection is still active.

When the parameters are set to the values specified in the following procedure, the server sends 20 watchdog packets (twice the default value) but sends them in the shortest time allowed. If there is no response from the workstation, the server disconnects the workstation and displays an alert on the console.


Procedure

  1. At the server console prompt, load either SERVMAN or MONITOR.

    LOAD SERVMAN | MONITOR <Enter>

    NOTE:  You can also set parameters with the SET command. See SET in Utilities Reference.

    2.

  2. Choose Server Parameters from the Available Options menu.

    3.

  3. Choose Communications from the Categories menu.

    4.

  4. Change the following watchdog parameters to the indicated values:

    Number of Watchdog Packets=20

    Delay Between Watchdog Packets=10

    Delay Before First Watchdog Packet=16

    Console Display Watchdog Logouts=ON

    5.

  5. Press <Esc> twice to reach the Update Options menu.

    6.

  6. Choose Update AUTOEXEC.NCF and STARTUP.NCF Now from the Update Options menu.

    A window appears, indicating the path to the AUTOEXEC.NCF file.

    7.

  7. If desired, press <Enter> to update the file.

    The system writes the parameters to the AUTOEXEC.NCF file or updates the parameters if they are already in the file.

    If you do not update the AUTOEXEC.NCF file, the parameter changes last only until the server is rebooted.

    8.

Additional Information

For more information about See

Watchdog packets

Watchdog in Concepts

SET parameters

SET in Utilities Reference

Using SERVMAN to set parameters

SERVMAN in Utilities Reference

Increasing the Maximum Number of Packet Receive Buffers

Packet receive buffers store incoming data packets until they can be processed by the server.

You should increase the maximum number of packet receive buffers only if the server is running out of buffers. The server is running out of buffers if it is

The General Information window of MONITOR displays the total number of currently allocated packet receive buffers.


Procedure

  1. At the server console prompt, load either SERVMAN or MONITOR.

    LOAD SERVMAN | MONITOR <Enter>

    NOTE:  You can also set parameters with the SET command. See SET in Utilities Reference.

    2.

  2. Choose Server Parameters from the Available Options menu.

    3.

  3. Choose Communications from the Categories menu.

    4.

  4. Choose Maximum Packet Receive Buffers.

    5.

  5. Increase the value of this parameter and press <Enter>.

    A good rule of thumb is to set this value to twice the size of the Minimum Packet Receive Buffer value.

    For other suggestions, see the discussion of the Maximum Packet Receive Buffer parameter under SET in Utilities Reference.

    6.

  6. Press <Esc> twice to reach the Update Options menu.

    7.

  7. Choose Update AUTOEXEC.NCF and STARTUP.NCF Now from the Update Options menu.

    You are prompted to update the STARTUP.NCF file.

    8.

  8. If the SET parameter is in the STARTUP.NCF file, press <Enter> to update the value in the file. Otherwise press <Esc>.

    You are prompted to update the AUTOEXEC.NCF file.

    9.

  9. If desired, press <Enter> to update the value in the file. Otherwise, press <Esc>.

    If you press <Enter> to update the file, the system writes the parameters to the AUTOEXEC.NCF file or updates the parameters if they are already in the file.

    10.

Increasing the Minimum Number of Packet Receive Buffers

The operating system allocates a minimum number of packet receive buffers as soon as the server boots. The minimum number is specified by the Minimum Packet Receive Buffer SET parameter.

Refer to the Packet Receive Buffer value in the General Information window of MONITOR to determine how many buffers the server is currently allocating.

Use the following procedure to increase the minimum number of packet receive buffers if


Procedure

  1. At the server console prompt, load either SERVMAN or MONITOR.

    LOAD SERVMAN | MONITOR <Enter>

    NOTE:  You can also set parameters with the SET command. See SET in Utilities Reference.

    2.

  2. Choose Server Parameters from the Available Options menu.

    3.

  3. Choose Communications from the Categories menu.

    4.

  4. Choose Minimum Packet Receive Buffers.

    5.

  5. Increase the value of this parameter.

    As a rule of thumb, allocate at least two packet receive buffers for each workstation connection.

    For other suggested settings, see the discussion of the Minimum Packet Receive Buffer parameter under SET in Utilities Reference.

    NOTE:  The Minimum Packet Receive Buffers value should be smaller than the Maximum Packet Receive Buffers value. If it is greater than the maximum value, the system changes the maximum value to match the minimum value.

    6.

  6. Press <Esc> twice to reach the Update Options menu.

    7.

  7. Choose Update AUTOEXEC.NCF and STARTUP.NCF Now from the Update Options menu.

    A window appears, indicating the path to the STARTUP.NCF file.

    8.

  8. Press <Enter> to update the file.

    The system places the parameter in the STARTUP.NCF file the next time the server boots. The parameter can be set only in the STARTUP.NCF file.

    9.

  9. When you want the changes to take effect, reboot the server.

    10.

Avoiding Bottlenecks During Peak Usage

Use this procedure if your server is slow to respond during periods of heavy use.

This procedure decreases the value of the New Packet Receive Buffer Wait Time SET parameter, which specifies how long the server must wait before granting a new packet receive buffer. By decreasing the value of this parameter you cause the system to grant buffers more quickly.

You may also want to increase the value of the Minimum Packet Receive Buffers parameter. See Increasing the Minimum Number of Packet Receive Buffers.


Procedure

  1. At the server console prompt, load either SERVMAN or MONITOR.

    LOAD SERVMAN | MONITOR <Enter>

    NOTE:  You can also set parameters with the SET command. See SET in Utilities Reference.

    2.

  2. Choose Server Parameters from the Available Options menu.

    3.

  3. Choose Communications from the Categories menu.

    4.

  4. Choose New Packet Receive Buffer Wait Time.

    5.

  5. Decrease the value of this parameter and press <Enter>.

    6.

  6. Press <Esc> twice to reach the Update Options menu.

    7.

  7. Choose Update AUTOEXEC.NCF and STARTUP.NCF Now from the Update Options menu.

    A window appears, indicating the path to the AUTOEXEC.NCF file.

    8.

  8. If desired, press <Enter> to update the file.

    If you press <Enter>, the system writes the parameter to the AUTOEXEC.NCF file or updates the parameter if it is already in the file. The file is updated immediately. You do not need to reboot the server.

    If you do not press <Enter>, the parameter change lasts only until you reboot the server.

    9.


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