Configuring the Natural Development Server

#### Search Results

Search

# Configuring the Natural Development Server

This document describes how to configure a Natural Development Server for z/OS (Com-plete).

The following topics are covered:

- Configuration Requirements

- NDV Configuration File

- NDV Configuration Parameters

- NDV Configuration File Example

- NDV Server Datasets

- NDV User Exits (Coded in Natural)

- Other NDV User Exits

- Encrypted Communication

- Configuring Port Sharing

## Configuration Requirements

The following topics are covered below:

- SMARTS SYSPARM Parameters

- SYSPARM Example for the Natural Development Server

### SMARTS SYSPARM Parameters

The Natural Development Server requires the following SMARTS `SYSPARM` parameters:

Parameter | Definition
--- | ---
`RESIDENTPAGE` | The following members must be defined in the SMARTS resident area: `NATRDEVS`, `NATMONI`, `NATDSSEC`, Natural front-end (`NCFNUC`) and Natural nucleus (if you run using a split nucleus).
`SECSYS` | The installed external security system (`RACF` | `ACF2` | `TOPSECRET`).
`SERVER` | The following `SERVER` definitions are required for the Natural Development Server:
`SERVER=(OPERATOR,TLINOPER,TLSPOPER)` | The Operator Communications Server.
`SERVER=(POSIX,PAENKERN)` | The POSIX Server.
The Natural local buffer pool definition. | For details, refer to the Natural Com-plete interface documentation.
`CDI_DRIVER` | `CDI_DRIVER=('TCPIP,PAAOSOCK')` | The SMARTS TCPIP Socket Driver for TCP/IP stack on z/OS (Com-plete).
`THSIZEABOVE` | `THSIZEABOVE=1024` | The storage above 16 MB that is available for each Natural Development Server subtask. This size must be large enough to keep the Natural tread, heap and stack of the Natural Development Server subtasks. A certain headroom (20 % or more, depending on your environment) is recommended. If the Natural Development Server initialization fails with an error message `NAT9915 GETMAIN for thread storage failed`, this parameter must be increased.
`ADASVC` | `ADASVC=nnn` | The Adabas SVC number of your Adabas installation.

You can set the SMARTS `SYSPARM` parameters in the file referred by DD-name `SYSPARM` within your Com-plete startup JCL.

### SYSPARM Example for the Natural Development Server

In the following example, the notation `vrs` or `vr` stands for the relevant version, release, system maintenance level numbers. The currently applicable product version must be installed; refer to Empower at https://empower.softwareag.com/.

    * ------------------ NDV Server to launch at startup ----------*
    * STARTUPPGM='NATRDEVS NDVvr'
    *
    *
    TASK-GROUP=(DEFAULT,6)
    THREAD-GROUP=(DEFAULT,(DEFAULT,252,06,15,28,N))
    *
    THSIZEABOVE=1024
    *
    SERVER=(NCFNATvr,NCFNATvr)
    *
    CDI_DRIVER=('TCPIP,PAAOSOCK,ADDRSPCE=...')
    *
    RESIDENTPAGE=NATRDEVS
    RESIDENTPAGE=NDVNCFvr
    RESIDENTPAGE=NATNUCvr
    RESIDENTPAGE=NATHTMON
    RESIDENTPAGE=NATMONI
    RESIDENTPAGE=NATDSSEC

`ADDRSPCE` should contain the name of the TCP/IP address space.
`NDVNCFvr` is the name of the Natural Complete Frontend.
`NATNUCvr` is the name of the Natural Nucleus.

## NDV Configuration File

A configuration file is allocated to the name `<serverid>C` (for example, ) or `STGCONFG` alternatively.

The configuration file is a text file located on a dataset under z/OS.

The configuration file contains the server configuration parameters in the form of a `keyword=value` syntax. In addition, it may contain comments whose beginning is marked with a hash symbol (#).

See also the NDV Configuration File Example shown below.

## NDV Configuration Parameters

The following NDV configuration parameters are available:

- CPU_TIME_TRACE

- CPU_TIME_HISTORY

- DBG_CODEPAGE

- DEFAULT_PROFILE

- FORCE_IPV4

- FRONTEND_NAME

- HANDLE_ABEND

- HOST_NAME

- HTPMON_ADMIN_PSW

- HTPMON_PORT

- HOST_NAME

- INITIAL_USERID

- MINIMUM_STUDIO_VERSION

- O4I

- PARMCHECK

- PASSWORD_MIXEDCASE

- PORT_NUMBER

- SECURITY_MODE

- SESSION_PARAMETER

- SESSION_PARAMETER_MIXED_CASE

- SESSION_TIMEOUT

- TERMINAL_EMULATION

- TRACE_FILTER

- TRACE_LEVEL

- UNICODE_SOURCE

- UPPERCASE_SYSTEMMESSAGES

### CPU_TIME_TRACE

This optional configuration parameter specifies a time limit of central processing unit (CPU) time of a transaction. Transactions with a higher CPU time usage than the specified time limit are traced in the trace file. Trace level 30 is required to enable the trace. There are two types of traces: one that shows the CPU time of a single transaction and one that shows the CPU time of an entire session.

Note
A session consists of several transactions.

Example of traces of session DEBE5E3816036616:

    04 14:21:34 00000052 Execute cpu time of session DEBE5E3816036616: 0.001295 s
    04 14:25:51 00000052 Total cpu time of session DEBE5E3816036616: 0.063536 s

The value of `CPU_TIME_TRACE` applies also to the `CPU_TIME_HISTORY` parameter if specified.

The parameter can be changed dynamically in the configuration menu of the HTML Monitor.

Value | Explanation
--- | ---
`time-limit` | CPU time limit in seconds written as a decimal. Valid values are from `0,0` to `65535,0`.
`120,0` | `120,0` seconds. This is the default value.

Example:

    CPU_TIME_TRACE=1,0

The setting in the example traces transactions and sessions with higher CPU time usage than 1,0 seconds.

### CPU_TIME_HISTORY

This optional configuration parameter specifies a buffer that stores the specified number of transactions with the highest central processing unit (CPU) time values.

The entries are sorted by CPU time in descending order. Each stored entry contains the CPU time, the session ID, the day and time, the user ID and type of transaction executed.

The list can be displayed with the HTML Monitor Client in a browser window or with Monitor Client NATMOPI. The number of stored entries can be filtered by setting a CPU time limit with `CPU_TIME_TRACE`. The parameter can be changed dynamically in the configuration menu of the HTML Monitor.

Value | Explanation
--- | ---
`time_history_integer` | Stores the number of highest CPU time values provided. The values are sorted by CPU time in descending order. Valid values are from 1 to 100, and `NO`.
`NO` | CPU time history is off. This is the default value.

Example:

    CPU_TIME_HISTORY=32

The setting in the example stores the 32 highest CPU time values sorted by cpu time.

### DBG_CODEPAGE

This optional configuration parameter specifies the translation table to be used by the remote debugger. By default, the remote debugger uses the code page `IBM-1047`, whereas the Natural Development Server uses `TABA1/2`.

Value | Explanation
--- | ---
`USER` | Use the Natural translation tables `TABA1/2`.

No default value is provided.

Example:

    DBG_CODEPAGE=USER

### DEFAULT_PROFILE

This optional configuration parameter defines a default profile.

Value | Explanation
--- | ---
`string` | The following syntax applies:
    profile-name,dbid,fnr,password,cipher-code
Note: Specifying a parameter string in the Session Parameters text box of the Map Environment dialog box in Natural Studio overwrites this default profile.

No default value is provided.

Example:

    DEFAULT_PROFILE=RDEVS,10,930

The setting in the example defines that, if no parameters are defined in the Map Environment dialog box of Natural Studio, the session is started with the Natural profile parameter `PROFILE=(RDEVS,10,930)`.

Related parameter: `SESSION_PARAMETER`.

### FORCE_IPV4

This configuration parameter applies to z/OS.

This parameter allows you to enforce the use of communication method IPV4.

Value | Explanation
--- | ---
`YES` | Enforce the use of communication method IPV4.
`NO` | First try communication method IPV6. If this fails give an error message and use communication method IPV4. This is the default value.

### FRONTEND_NAME

This configuration parameter specifies the name of the Natural front-end to be used to start a Natural session. The front-end resides on a PDS member.

Value | Explanation
--- | ---
`frontend-name` | Natural front-end to be used. Maximum length: 8 characters.

No default value is provided.

Example:

    FRONTEND_NAME=NATvrsSV

- where vrs stands for the version, release, system maintenance number.

### HANDLE_ABEND

If an abend occurs in the server processing outside the Natural processing the abend is not trapped by the Natural abend handling. For this reason the NDV server has its own abend recovery.

It is recommended that you leave this parameter on its default value in order to limit the impact of an abend to a single user. If you set the value of this parameter to `NO`, any abend in the server processing terminates the complete server processing. That is, it affects all users running on that server.

Value | Explanation
--- | ---
`YES` | Trap abends in the server processing, write a snap dump and abort the affected user. This is the default value.
`NO` | Suspend the server abend handling.

Example:

    HANDLE_ABEND=NO

### HOST_NAME

This optional configuration parameter is necessary only if the server host supports multiple TCP/IP stacks.

Value | Explanation
--- | ---
`host-name` | If `HOST_NAME` is specified, the server listens on the particular stack specified by `HOST_NAME`, otherwise the server listens on all stacks.

No default value is provided.

Example:

    HOST_NAME=node1

or

    HOST_NAME=157.189.160.55

### HTPMON_ADMIN_PSW

This configuration parameter defines the password required for some monitor activities (for example, `Terminate Server`) performed by the HTML Monitor Client.

Value | Explanation
--- | ---
any character string | The password to be entered at the HTML Monitor Client for some monitor activities.

No default value is provided.

Example:

    HTPMON_ADMIN_PSW=GHAU129B

### HTPMON_PORT

An NDV server can be configured to host an HTTP monitor task which serves the HTML Monitor Client running in a web browser. It is not required to run this monitor task on each server. A single task allows you to monitor all servers running at one node.

This configuration parameter defines the TCP/IP port number under which the server monitor task can be connected from a web browser.

Value | Explanation
--- | ---
`1 - 65535` | TCP/IP port number.

No default value is provided.

Example:

    HTPMON_PORT=3141

### HOST_NAME

This configuration parameter defines the host name of the NDV server.

### INITIAL_USERID

At server initialization, the Natural Development Server creates a temporary Natural session to obtain the properties of the installed Natural environment.

This configuration parameter specifies the user ID to be used for this Natural session.

Value | Explanation
--- | ---
`userid` | The specified value must not exceed 8 characters, otherwise it is truncated.
`STARGATE` | This is the default value.

Example:

    INITIAL_USERID=NDVINITU

See also (in the Natural Development Server Installation documentation).

### MINIMUM_STUDIO_VERSION

This parameter defines a minimum version of Natural Studio which is required to operate with the NDV server. This parameter assists in performing a preliminary validation if all clients use a minimum Natural Studio version. This can be useful to smoothly upgrade to a NDV version that does not support clients whose version is below the minimum Natural Studio version.

Value | Explanation
--- | ---
`vvmmpp` | The Studio Version (5-6 digits), where:
vv | Version number (1 or 2 digits).
mm | System maintenance level (2 digits).
pp | Patch level (2 digits).
`61100` | This is the default value.

Example:

    MINIMUM_STUDIO_VERSION=62100

### O4I

This parameter allows you to collect server data for Optimize for Infrastructure.

Value | Explanation
--- | ---
`YES` | Collect server data for Optimize for Infrastructure.
`NO` | Do not collect server data for Optimize for Infrastructure. This is the default value.

Example:

    O4I=YES

### PARMCHECK

This parameter allows you to perform a parameter check of Natural session parameters after the server is up. The check is done by mapping to Natural. If a problem occurs, a message is written to the NDV server trace, and the server is terminated immediately. In such cases, session parameters (`SESSION_PARAMETER`) can be corrected. To avoid termination of the server in case of invalid Natural parameters, the parameter check can be switched off.

This parameter does not apply with `SECURITY_MODE=IMPERSONATE`, `IMPERSONATE_LOCAL`, or `IMPERSONATE_REMOTE`.

Value | Explanation
--- | ---
`YES` | Perform parameter check after the server is up. This is the default value.
`NO` | Avoid parameter check after the server is up.

Example:

    PARMCHECK=NO

### PASSWORD_MIXEDCASE

This parameter allows you to define whether passwords specified in the Map Environment dialog are translated into upper case or not.

This parameter does only apply with `SECURITY_MODE``=IMPERSONATE, IMPERSONATE_LOCAL` or `IMPERSONATE_REMOTE`.

Value | Explanation
--- | ---
`YES` | Passwords remain in mixed case.
`NO` | Passwords are translated into upper case. This is the default value.

Example:

    PASSWORD_MIXEDCASE=YES

### PORT_NUMBER

This configuration parameter defines the TCP/IP port number under which the server can be connected.

Value | Explanation
--- | ---
`1 - 65535` | TCP/IP port number.

No default value is provided.

Example:

    PORT_NUMBER=3140

### SECURITY_MODE

The Natural Development Server offers a security concept that also covers the operating system resources. The client credentials are validated at the operating-system-depending security system and the client request is executed under the client's account data.

Using the `SECURITY_MODE` parameter, you can specify at which rank (Batch) you want to impersonate the activities of an NDV client.

Value | Explanation
--- | ---
`IMPERSONATE_LOCAL` | Impersonation is done within the Natural Development Server environment. If the session is dispatched in a remote TP environment, it is still executed anonymous. The client must be defined in the security system of the NDV server. It is not required to define the client in a remote TP environment.
`IMPERSONATE_REMOTE` | No impersonation is done within the Natural Development Server environment. If the session is dispatched in a remote TP environment, the client is impersonated. The client must be defined in the security system of the remote TP environment.
`IMPERSONATE` | Impersonation is done within the Natural Development Server environment and in a remote TP environment. The client must be defined in the security system of the NDV server and in the remote TP environment.

Note
For a batch server `SECURITY_MODE=IMPERSONATE` and `SECURITY_MODE=IMPERSONATE_LOCAL` are the same.

`SECURITY_MODE` requires Natural Security (NSC).

No default value is provided.

Example:

    SECURITY_MODE=IMPERSONATE

### SESSION_PARAMETER

This optional configuration parameter defines session parameters that precede the parameter string either specified in the Map Environment dialog of Natural Studio or defined by default by the configuration parameter `DEFAULT_PROFILE`.

Value | Explanation
--- | ---
`parameter-string` | This string may extend across several lines. A plus sign (+) at the end of a string line denotes that another line follows.

No default value is provided.

Example 1:

    SESSION_PARAMETER='NUCNAME=NATNUCvr' +
      'PROFILE=(NDVPARM,18006,48),ADAMODE=0,' +
      'BPI=(TYPE=NAT,SIZE=6044),BPI=(TYPE=EDIT,SIZE=2048)', +
      'BPI=(TYPE=SORT,SIZE=1024)'

- where `vr` stands for the version and release number.

Example 2:

    SESSION_PARAMETER=FNAT=(10,930)

The setting in the second example defines that every session on this Natural Development Server is started with the session parameter `FNAT=(10,930)` appended to the user-specified parameters or the definitions in the configuration parameter `DEFAULT_PROFILE`.

### SESSION_PARAMETER_MIXED_CASE

This optional configuration parameter can be used to allow session parameters and URL specifications in mixed case.

Value | Explanation
--- | ---
`YES` | Session parameters remain in mixed case.
`NO` | Session parameters are translated into upper case. This is the default value.

### SESSION_TIMEOUT

Cancel inactive sessions when the `SESSION_TIMEOUT` parameter is met. Check for sessions inactive longer then `n` minutes once a day at `HH:MM` (24 hours) or every `n` minutes.

The server will not start if an invalid `SESSION_TIMEOUT` parameter is given.

Value | Explanation
--- | ---
`hh:mm,n <numeric value greater than 0>` or `m <numeric value greater than 0>,n <numeric value>0>` | If format is `hh:mm`, check once a day at `hh:mm` for sessions more than `n` minutes inactive. or If format is a numeric value, check every `m` minutes for sessions more than `n` minutes inactive.

Examples:

    SESSION_TIMEOUT=19:30,480

Every day at 19:30 cancel sessions more than 480 minutes inactive.

    SESSION_TIMEOUT=360,480

Every 360 minutes cancel sessions more than 480 minutes inactive.

### TERMINAL_EMULATION

This configuration parameter defines the terminal emulation to be used for processing the Natural I/O. This definition applies to all clients using that server.

Value | Explanation
--- | ---
`WEBIO` | Use the Web I/O Interface as terminal emulation.
`3270` | Use the 3270 terminal emulation. This is the default value.

Example:

    TERMINAL_EMULATION=WEBIO

### TRACE_FILTER

This optional configuration parameter enables you to restrict the trace by a logical filter in order to reduce the volume of the server trace output, for example:

    TRACE_FILTER="Client=(KSP P*)"

Each request of the user ID `KSP` and each request of the user IDs starting with a `P` are traced.

See Trace Filter in the section Operating the Natural Development Server.

### TRACE_LEVEL

Value | Explanation
--- | ---
`trace-level` | See Trace Level in the section Operating the Natural Development Server.
`0` | This is the default value.

Example:

    TRACE_LEVEL=0x00000011

or alternatively

    TRACE_LEVEL=31+27

The setting in the example switches on Bits 31 and 27.

### UNICODE_SOURCE

This configuration parameter is used to define whether the NDV server accepts source files in Unicode or not.

Sources transmitted in unicode are not converted using the Natural ASCII-to-EBCDIC translation tables `TABA1/TABA2`. All characters in the source file are supported without maintaining the Natural translation tables.

A transmission in Unicode, however, increases the CPU consumption of the server significantly.

Value | Explanation
--- | ---
`YES` | Transfer sources in Unicode.
`NO` | Transfer sources in ASCII. No code page support for Natural sources. This is the default value.

Example:

    UNICODE_SOURCE=YES

### UPPERCASE_SYSTEMMESSAGES

This configuration parameter is used to enable or disable the translation of all NDV error messages and trace outputs to uppercase. This feature is for customers who are using character sets with no lowercase characters defined.

Value | Explanation
--- | ---
`YES` | Enable uppercase translation.
`NO` | Disable uppercase translation. This is the default value.

## NDV Configuration File Example

    # This is a comment
    SESSION_PARAMETER=profile=(stgqa,10,930) fuser=(10,32)
    DEFAULT_PROFILE=DEFPROF
    FRONTEND_NAME=NATNCF       # and another comment
    PORT_NUMBER=4711

## NDV Server Datasets

The Natural Development Server requires the following datasets:

`STGCONFG` | Defines the server configuration file.
`STGTRACE` | The server trace output.
`STGSTDO` | The stdo dataset.
`STGSTDE` | The stde error output.

Alternatively, you can qualify each dataset name by the server ID. This is necessary if you want to start different Natural Development Servers under a single SMARTS address space.

`NDVS1C` | Defines the server configuration file for the server `NDVS1`.
`NDVS1T` | The server trace output for the server `NDVS1`.
`NDVS1O` | The stdo dataset for the server `NDVS1`.
`NDVS1E` | The stde error output for the server `NDVS1`.

## NDV User Exits (Coded in Natural)

Natural Single Point of Development provides the following user exits for mainframes:

`NDV-UX01` | This exit is invoked before a Natural source object or a DDM is edited. It can be used to reject editing of certain sources. The source code of this exit is delivered in the library `SYSLIB` and named `NDV-SX01` *).
`NDV-UX02` | This exit is invoked before a Natural object, a DDM or a user error message is deleted, copied or moved (including the context menu functions Cut, Copy and Paste). It enables the rejection of further processing of this object, similar to the user exit `MAINEX01` of `SYSMAIN` in Natural for Mainframes. The source code of this exit is delivered in the library `SYSLIB` and named `NDV-SX02` *).
`NDV-UX03` | This exit provides flags for special settings within the Natural Development Server. See the source code of this exit for available flags. The source code of this exit is delivered in the libary `SYSLIB` and is named `NDV-SX03` *).

*) The sources of these user exit routines are named `NDV-SXnn`, where `nn` denotes the number of the user exit routine.

To make a user exit routine available

1. Copy the source code from `SYSLIB` into a user library.

2. Catalog it under the name `NDV-UXnn`.

3. Copy it back into the Natural system library `SYSLIB`.

The name of each user exit source is different from the name of the corresponding cataloged object. This guarantees that the object is not affected if the user exit source is overwritten by an installation update.

For further details, see the source code of the user exit routines `NDV-SXnn` in the Natural system library `SYSLIB`.

## Other NDV User Exits

Apart from the NDV user exits that are coded in Natural, the following user exit exists:

### User Exit NSECUX01

This user exit is applicable only when the parameter `SECURITY_MODE` is set to `IMPERSONATE_LOCAL` or `IMPERSONATE`.

This user exit allows you to adapt the user ID used for the RACF login. It is useful if the RACF user IDs and the user IDs used in Natural differ according to a standardized rule. For example, each RACF user ID is the corresponding Natural user ID preceded by two dollar signs ($$).

If the exit (the loadmodule `NSECUX01`) is found in the NDV load library concatenation, it is called using standard linkage conventions (direct branch using BASR instructions) before the user is validated against RACF.

The following parameters are passed to the exit:

Name | Format | In/Out | Description
--- | --- | --- | ---
sUid | CL64 | I/O | User ID to be modified for RACF login.

The exit is called using standard linkage conventions.

Sample user exit implemented in C:

    #include <string.h>
    #include <stdio.h>
    #  pragma linkage (NSECUX01, FETCHABLE)
    void NSECUX01(char sUid[64])
    {
    char sUidTemp[64];
      printf("Uex got usid:%s\n", sUid);
      strcpy(sUidTemp, sUid);
      sprintf(sUid, "$$%s", sUidTemp);
      printf("Uex ret usid:%s\n", sUid);
      return;
    }

The exit above extends each user ID by two preceding dollar signs ($$) when it is used for RACF login.

## Encrypted Communication

Communication between NaturalONE and NDV servers can be encrypted by using an SSL or (preferably) a TLS protocol.

On the server side, encryption is enabled by using the AT-TLS component of the z/OS Communications Server. AT-TLS allows you to encrypt and secure the TCP/IP communication between client and server without any changes on the server side. If you want to use encrypted communication mode, you must define a set of rules concerning the NDV server job for the policy agent (PAGENT) configuration file of AT-TLS. Encrypted communication requires a certificate associated with encryption on the server side. This encryption certificate must either be included in a RACF keyring or stored in a key database located on the z/OS USS POSIX file system.

Use the ZOSMF utility for maintaining the PAGENT.

For detailed information on AT-TLS, refer to the z/OS Communications Server documentation from IBM.

### SSL/TLS Support

- SSL/TLS over AT-TLS
- Maintenance of Certificates under z/OS
- Using RACF Key Rings
- Using Key Databases
- How to configure TCP/IP for AT-TLS?
- How to Verify AT-TLS Configuration?
- Frequently Asked Questions
- Generation of a Natural development Server Certificate

#### SSL/TLS over AT-TLS

SSL/TLS support for the Natural development server is based on the z/OS Communication Server component AT-TLS (Application Transparent-Transport Layer Security).

AT-TLS provides SSL/TLS encryption as a configurable service for sockets applications. It is realized as an additional layer on top of the TCP/IP protocol stack, which exploits the SSL/TLS functionality in nearly or even fully transparent mode to sockets applications. AT-TLS offers three modes of operation. See z/OS Communications Server, IP Programmer’s Guide and Reference. Chapter: Application Transparent Transport Layer Security (AT-TLS).

These modes are:

- #### Basic

  The sockets application runs without modification in transparent mode, unaware of performing encrypted communication via AT-TLS. Thus legacy applications can run in secured mode without source code modification.

- #### Aware

  The application is aware of running in secured mode and is able to query TLS status information.

- #### Controlling

  The sockets application is aware of AT-TLS and controls the use of AT-TLS encryption services itself. This means, the application is able to switch between secured and non secured communication.

Natural development server uses the Basic mode for its SSL/TLS implementation. That is, a server configured as SSL/TLS server rejects requests from non-secured clients.

#### Maintenance of Certificates under z/OS

Certificates, which are to be used with AT-TLS, can be maintained in two ways under z/OS. They are stored either in RACF key rings or in key databases, which are located in the z/OS Linux file system. Which of these proceedings actually applies is defined in the AT-TLS Policy Agent Configuration file for the z/OS TCP/IP stack, which is used by the Natural HTTPS client.

IBM delivers a set of commonly used CA root certificates with each z/OS system delivery. If key rings are going to be used to hold server certificates, those root certificates must be manually imported into the key rings by the system administrator. If IBM delivers newer replacements for expired root certificates, all affected key rings have to be updated accordingly.

Unlike key rings, key databases contain the current set of root certificates automatically after they have been newly created. However, the need for maintaining always the latest set of root certificates applies to the key database alternative as well.

#### Using RACF Key Rings

In RACF, digital certificates are stored in so-called key rings. The RACF command `RACDCERT` is used to create and maintain key rings and certificates, which are contained in those key rings.

See z/OS Security Server RACF Security Administrator’s Guide, Chapter: RACF and digital certificates - RACF and key rings, and z/OS Security Server RACF, Command Language Reference, Chapter: RACF command syntax - RACDCERT.

#### Using Key Databases

Alternatively to RACF, certificates can be kept in key databases, which reside in the z/OS Linux services file system. For the creation and maintenance of key databases, the `GSKKYMAN` utility has to be used.

See z/OS Cryptographic Services PKI Services Guide and Reference, Chapter: Appendix B. Using a gskkyman key database for your certificate store.

#### How to configure TCP/IP for AT-TLS?

Proceed as follows:

1. In the TCP/IP configuration file, set the option `TTLS` in the `TCPCONFIG` statement.

2. Configure and start the AT-TLS Policy Agent. This agent is called by TCP/IP on each new TCP connection to check if the connection is SSL/TLS.

3. Create the Policy Agent file containing the AT-TLS rules. The Policy Agent file contains the rules to stipulate which connection is SSL/TLS.

See also z/OS Communications Server: IP Configuration Guide, Chapter: Application Transparent Transport Layer Security data protection.

The Sample Policy Agent file defines the server with the job name starting with `NDVDEV` and listening at port 4843 to use SSL/TLS.

The sample expects the certificate database on the HFS file /u/admin/CERT.kdb.

    TTLSRule                          ConnRule01~1
    {
      LocalAddrSetRef                 addr1
      RemoteAddrSetRef                addr1
      LocalPortRangeRef               portR1
      RemotePortRangeRef              portR2
      Jobname                         NDVDEV*
      Direction                       Inbound
      Priority                        255
      TTLSGroupActionRef              gAct1~NDV_Server
      TTLSEnvironmentActionRef        eAct1~NDV_Server
      TTLSConnectionActionRef         cAct1~NDV_Server
    }
    TTLSGroupAction                   gAct1~NDV_Server
    {
      TTLSEnabled                     On
    }
    TTLSEnvironmentAction             eAct1~NDV_Server
    {
      HandshakeRole                   Server
      EnvironmentUserInstance         0
      TTLSKeyringParmsRef             keyR1
    }
    TTLSConnectionAction              cAct1~NDV_Server
    {
      HandshakeRole                   Server
      TTLSCipherParmsRef              cipher1~AT-TLS__Silver
      TTLSConnectionAdvancedParmsRef  cAdv1~NDV_Server
    }
    TTLSConnectionAdvancedParms       cAdv1~NDV_Server
    {
      CertificateLabel                NDV_TEST_CERT
    }
    TTLSKeyringParms                  keyR1
    {
      Keyring                         /u/admin/CERT.kdb
      KeyringStashFile                /u/admin/CERT.sth
    }
    TTLSCipherParms                   cipher1~AT-TLS__Silver
    {
      V3CipherSuites                  TLS_RSA_WITH_DES_CBC_SHA
      V3CipherSuites                  TLS_RSA_WITH_3DES_EDE_CBC_SHA
      V3CipherSuites                  TLS_RSA_WITH_AES_128_CBC_SHA
    }
    IpAddrSet                         addr1
    {
      Prefix                          0.0.0.0/0
    }
    PortRange                         portR1
    {
      Port                            4843
    }
    PortRange                         portR2
    {
      Port                            1024-65535
    }

#### How to Verify AT-TLS Configuration?

Check Policy-Agent job output `JESMSGLG` for:

    EZZ8771I PAGENT CONFIG POLICY PROCESSING COMPLETE FOR <your TCP/IP address space>: TTLS

This message indicates a successful initialization.

Check Policy-Agent job output `JESMSGLG` for:

    EZZ8438I PAGENT POLICY DEFINITIONS CONTAIN ERRORS FOR <your TCP/IP address space>: TTLS

This message indicates errors in the configuration file. Check the syslog.log file for further information.

Does the configuration rule cover the server?

Try to connect the server and check syslog.log for:

    EZD1281I TTLS Map   CONNID: 00018BED LOCAL: 10.20.91.61..4843 REMOTE: 10.20.160.47..4889 JOBNAME: NDVDEVvr USERID: NDVSRV TYPE: InBound STATUS: Enabled RULE: ConnRule01~1 ACTIONS: gAct1 eAct1~NDV_Server cAct1~NDV_Server

The above entry indicates that the connection to Port 4843 is SSL/TLS enabled.

#### Frequently Asked Questions

#### Is there more information about problem determination?

See z/OS Communications Server, IP Diagnosis Guide, Chapter: Diagnosing Application Transparent Transport Layer Security (AT-TLS)

#### How to switch on P-agent trace?

See z/OS Communications Server, IP Configuration Reference, Chapter: Syslog deamon, and z/OS Communications Server, IP Configuration Guide, Chapter: Base TCP/IP system – TCP/IP Customization - Configuring the syslog daemon (syslogd).

#### Error at connection establishment

Find return code RC and corresponding `GSK_` function name in P-agent trace.

Get description of the return code from z/OS Cryptographic Services, System Security Sockets Layer Programming, Chapter: : messages and codes – SSL function return codes.

Sample trace with `trace=255`:

    EZD1281I TTLS Map   CONNID: 00002909 LOCAL: 10.20.91.61..1751 REMOTE: 10.20.91.117..443 JOBNAME: KSP USERID: KSP TYPE: OutBound STATUS: A
    EZD1283I TTLS Event GRPID: 00000003 ENVID: 00000000 CONNID: 00002909  RC:    0 Connection Init
    EZD1282I TTLS Start GRPID: 00000003 ENVID: 00000002 CONNID: 00002909 Initial Handshake ACTIONS: gAct1 eAct1 AllUsersAsClient HS-Client
    EZD1284I TTLS Flow  GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:    0 Call GSK_SECURE_SOCKET_OPEN - 7EE4F718
    EZD1284I TTLS Flow  GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:    0 Set GSK_SESSION_TYPE -  CLIENT
    EZD1284I TTLS Flow  GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:    0 Set GSK_V3_CIPHER_SPECS -  090A2F
    EZD1284I TTLS Flow  GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:    0 Set GSK_FD - 00002909
    EZD1284I TTLS Flow  GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:    0 Set GSK_USER_DATA - 7EEE9B50
    EZD1284I TTLS Flow  GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:  435 Call GSK_SECURE_SOCKET_INIT - 7EE4F718
    EZD1283I TTLS Event GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:  435 Initial Handshake 00000000 7EEE8118
    EZD1286I TTLS Error GRPID: 00000003 ENVID: 00000002 CONNID: 00002909 JOBNAME: KSP USERID: KSP RULE: ConnRule01  RC:  435 Initial Handshake
    EZD1283I TTLS Event GRPID: 00000003 ENVID: 00000002 CONNID: 00002909  RC:    0 Connection Close 00000000 7EEE8118

#### Generation of a Natural development Server Certificate

Under z/OS, SSL/TLS certificates can be produced with the Linux System Services utility `GSKKYMAN`. The following steps have to be executed for the production of a new certificate, which is to be used for the SSL/TLS secured communication between Natural Web I/O Interface client and server:

1. Start a shell session out of TSO or connect via telnet to the z/OS Linux shell.

2. Start `GSKKYMAN`.

3. Create a new – or open an existing key database.

4. Create a self-signed certficate, for example, of type "User or server certificate with 2048-bit RSA key".

5. Export the certificate to a (HFS) file. Choose Base64 ASN.1 DER as export format.

This generated file can now be copied to the Natural development server client(s) using FTP with ASCII transfer format. On the client side, the received file should be stored with the file name suffix .CER. The certificate can now be used by the Natural development server client.

For more information on how to import the certificate, see the documentation of NaturalONE, Natural for Ajax > Configuration and Administration Configuring SSL.

If certificates are kept in a RACF key ring, the generated certificate has to be imported into the appropriate key ring using the `RADCERT` command.

Certificates, which are produced on a different platform, for example, on a Windows PC, can be imported into a RACF key ring or into a key database as well.

Detailed information about the use of the `GSKKYMAN` utility can be found in the IBM Communications server documentation, e.g in the following manuals:

z/OS Communications Server, IP Configuration Guide

or

z/OS Cryptographic Services, System Secure Sockets Layer Programming

For the generation of certificates under Windows, a free downloadable utility named Ikeyman is available on several websites. Ikeyman is an IBM product as well and maps the functionality of `GSKKYMAN` to the Windows platform.

## Configuring Port Sharing

The TCP/IP port sharing component of the z/OS TCP/IP Communications subsystem allows multiple listeners to listen on the same combination of port and IP address. To enable this in the TCP/IP stack, you must add the `SHAREPORT` or `SHAREPORTWLM` keyword to the PORT profile statement that reserves the TCP port for the server instances. You can find detailed information in section PORT Statement, chapter TCP/IP profile (PROFILE.TCPIP) and Configuration Statements of the IBM manual z/OS Communications Server: IP Configuration Reference found on their official website.

You can start the NDV server as explained in section Starting the Natural Development Server. You must define the used port with the `PORT_NUMBER` parameter in the configuration file of the NDV server. If port sharing is enabled, the started task can be executed multiple times to start multiple instances of an NDV server that listens on the same port.

Note
All servers must be started with the same configuration file.

- Server ID

- Reliability

- Scheduling

- TRACE, STDOUT, and STDERR

### Server ID

Since the server ID is used to identify a server in the server directory, you must set a unique server ID. The server ID is passed as a parameter to the NDV server. You must set the parameters in the PARM card of the started task. For example:

    //NDVSRV  EXEC PGM=NATRDEVS,REGION=0M,TIME=20,
    //  PARM=('POSIX(ON) STACK(64K,32K,ANY,FREE) TRAP(ON,NOSPIE) ',
    //    'TERMTHDACT(UADUMP),ENVAR(TZ=CET+0DST) /SERVERID')

### Reliability

If multiple NDV servers are listening on a port and one server fails, the workload can still be done by the remaining servers. From a user point of view, the service offered by the NDV server remains available.

### Scheduling

If a request for a new connection arrives, it is in the responsibility of the z/OS operating system to pass the request to one of the listening servers. The connections are distributed across the available servers using a weighted round-robin distribution based on the Servers' accept Efficiency Fractions (SEFs). Once a session is started, it is executed on this server, until it is finished.

You can identify a session in the trace file with the following piece of code:

    Start of Session:
    26 10:16:45 0000000E Worker task active, SID=DED9D087D842B606, client: USER

    End of session:
    26 10:21:53 0000000E Worker task disconnect, client: USER
    26 10:21:53 0000000E Free LTCB...and finish

### TRACE, STDOUT, and STDERR

Each server has its own `STGTRACE`, `STGSTDO`, and `STDSTGE`, which are part of the job log of each server. It is possible to redirect the output of the files to a sequential dataset, but you must ensure that each server is assigned its own sequential dataset. Otherwise, the output of the files cannot be assigned to a particular server.

### On this page

- Configuration Requirements
- NDV Configuration File
- NDV Configuration Parameters
- NDV Configuration File Example
- NDV Server Datasets
- NDV User Exits (Coded in Natural)
- Other NDV User Exits
- Encrypted Communication
- Configuring Port Sharing