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| Communications Access Methods for SAS/CONNECT and SAS/SHARE Software |
You must perform the following tasks or have knowledge of the following issues to configure the TCP/IP access method for SAS/CONNECT and SAS/SHARE:
| Installing the SAS/C Transient Library |
You should have already installed the SAS/C Transient Library. If you have not, the installation steps are provided in this section.
The TCP/IP access method requires the SAS/C Transient Library, which is included with both SAS/CONNECT and SAS/SHARE.
If your site is running Release 5.50 of the SAS/C Transient Library, either you must re-install it, thereby replacing it with a later version, or you must apply zap Z5500974 to your installed library. The zap is included on the install tape and is described in usage notes.
Steps for installing the SAS/C Transient Library follow:
The CNTL data set member ULCTRANL contains JCL that is updated with job, &prefix, and allocation information that you supplied in the SASEDITP member. If you run this job as supplied, it unloads the SAS/C Transient Library Release 5.50 or a subsequent release from your install tape to a data set named &prefix.SASC.TRANSLIB.
ALLOC F(CTRANS) DA('&prefix.SASC.TRANSLIB')
SHR &SU11
// CTRANS DD DSN=&prefix.SASC.TRANSLIB,
DISP=SHR
Note: If you choose to install your SAS/C Transient
Library to a link-list data set, you do not need to allocate it in your CLIST
and in your cataloged procedure. ![[cautionend]](../common/images/cautend.gif)
| Understanding the Function of Network Configuration Files |
The
operation of the TCP/IP access method depends on its ability
to access network configuration information from particular site-specific
files. The specific filenames are based on the particular vendor TCP/IP product.
SAS software uses the IBM TCPIP.DATA file or TCPPARMS file to determine resolver configuration and IBM defaults. SAS searches the following locations for configuration data sets in this order:
If your configuration file is not in one of the default locations, you may specify its location by setting the TCPIPPRF SAS option to the TCP/IP prefix of your IBM files. For example, if your TCPIP.DATA file is installed in SYS2.VER2.TCP.TCPIP.DATA, you should set the TCPIPPRF option to SYS2.VER2.TCP.
If you do not use IBM defaults for resolver configuration or you do not maintain a name server, see Understanding the Search Order for Locating Network Configuration Files for information about the rules for searching for configuration files.
Note: The SAS/C Transient Library
does not support the IBM TCP/IP files HOSTS.LOCAL and HOSTS.SITEINFO. The
previous SAS TCP/IP access method used these files through the Pascal Transient
Library Services (Release 6.07 and 6.08 TS404).
You can set the SAS/C environment variables that are used in the configuration data set selection by including a data set with the special ddname SASCTCPV. If a data set with this ddname is allocated to the SAS session, then its contents are read during the TCP access method initialization. Each logical record is assumed to contain an environment variable assignment of the form:
environment_variable_name=value
For example, if all your configuration files existed under the TCPIP_PREFIX names, you could include the following in your SASCTCPV data set:
//SASCTCPV DD * TCPIP_PREFIX=TCPCURR /*
If any of the SAS options controlling configuration data sets are specified,
they will override the values that are set in the SASCTCPV data set. For example,
the SAS option TCPIPPRF will take precedence over a TCPIP_PREFIX assignment
in the SASCTCPV data set.
Interlink provides an LSCNCOM interface to the SAS/C Transient Library. You should place the LSCNCOM routine and its alias L$CNCOM, in the link-list search order before the module that is supplied by SAS. The routine is dynamically loaded when the first call to the SAS socket library function is made. SAS searches the following locations for configuration data sets in this order:
SAS uses the Interlink name resolver and the ICSRSLV option to determine the order in which the Interlink name resolver (DNR) and the SAS/C resolver are used.
For details about the LSCNCOM interface, see the Interlink documentation.
| Understanding the Search Order for Locating Network Configuration Files |
An explanation of the search logic that is used by the SAS/C Transient Library is contained in the following sections.
The file that contains configuration information usually has a name
that is derived from the equivalent UNIX filename; for example, the OS/390
data set name ETC.HOSTS is derived from the UNIX filename
/etc/hosts.
The SAS/C Transient Library uses the following search logic to locate the file that contains configuration information:
hosts.
| Understanding the Search Order for Locating Host Names and Internet Addresses |
The SAS/C Transient Library uses the following search logic to locate host names and Internet addresses:
Determining the domain name in name-server queries follows the same logic as the UNIX operating system follows when it uses the domain statement of the RESOLV.CONF file. Name-server addresses are also determined from the RESOLV.CONF file.
The SAS/C Transient Library recognizes
only the first three name servers specified in this file. Both the UNIX operating
system and the SAS/C environment have
a limit of three name servers.
The HOSTS file contains Internet address and host-name pairs with an optional alias.
You use either the HOSTS file or the resolver program to locate host name and Internet address equivalents.
Use the following format to create a HOSTS file:
Internet-address host-name optional-alias
Example:
127.0.0.1 localhost loopback 151.174.130.8 bigserver.yourcompany.com bigserver 151.174.130.27 copland.yourcompany.com copland 151.174.130.28 ives.yourcompany.com ives 151.174.130.29 byrd.yourcompany.com byrd
If you have access to a UNIX system, see the
hosts(4) manual page for
more information.
If you have access to a UNIX system, you are advised to copy the
hosts file from the UNIX system to the OS/390 system and customize
it as necessary. Doing this prevents typographical errors that may occur if
you create a new file.
The SAS/C Transient Library searches for the HOSTS file, in the following order:
The SERVICES file contains a service name, port number, protocol group with an optional alias. For SAS/SHARE, you must specify server names and port assignments in the SERVICES file. For SAS/CONNECT, the default TELNET port number is used.
If you have access to a UNIX system, see the
services(4) manual page for more information.
If you have access to a UNIX system, you are advised to copy the
services file from the UNIX system to the OS/390 system and customize
it as necessary. Doing this prevents typographical errors that may occur if
you create a new file.
See Configuring the Server in the SERVICES File
for details about the SERVICES file.
The SAS/C Transient Library searches for the SERVICES file, in the following order:
The RESOLV.CONF file contains Internet address and corresponding host-name pairs within the domain. This file is used by the resolver program to find addresses of name servers that are used to locate host-name and Internet address equivalents.
You will use either the HOSTS file or the resolver program to locate host name and Internet address equivalents.
Use the following format to create a RESOLV.CONF file:
host-name Internet-address
Example:
domain yourcompany.com nameserver 151.174.166.251 nameserver 151.174.52.151 nameserver 151.174.52.113
If you have access to a UNIX system, see the
resolver(4) manual page for more information.
If you have access to a UNIX system, you are advised to copy the RESOLV.CONF
file from the UNIX system to the OS/390 system, and customize it as necessary.
Doing so prevents typographical errors that may occur if you create a new
file.
Note: If you are using the IBM
TCP/IP, you do not need to create this
file.
The SAS/C Transient Library searches for the OS/390 configuration file that is equivalent to the UNIX RESOLV.CONF file, in the following order:
| Knowing about Configuration File Naming Conventions |
SAS searches for configuration files by the common default prefix TCPIP. It is stored in a 26-character string array in L$CNDBA in the SAS/C Transient Library. The SERVICES file, for example, is named TCPIP.ETC.SERVICES. You may override this default using one of the following methods:
All but one of these methods sets a prefix in the system. However, setting the TCPIPPRF option, affects only the invoking user's current session.
Note: Most sites already have these files available for existing TCP/IP applications.
If your site already has TCP/IP applications running under the SAS/C library,
this step was probably completed when the SAS/C Transient
Library was installed.
The ETC high-level qualifier prepends a configuration file name with the ETC prefix; for example, ETC.HOSTS and ETC.SERVICES.
Note: When using the ETC prefix,
do not set the TCPIPPRF option to override the ETC high-level qualifier
and do not apply the zap to change the default value of the TCPIP prefix in
the SAS/C Transient Library. See Applying a Zap to Change the Default TCPIP Prefix for more information.
If you cannot use ETC at your site and if DS names do not conflict with the ETC high-level qualifier, you may use the default prefix to produce names such as TCPIP.ETC.HOSTS.
Note: When using the TCPIP prefix, do not set the
TCPIPPRF option to override the TCPIP prefix, and do not apply the zap to
change the default value of the TCPIP prefix in the SAS/C Transient
Library. See the next section for details about the default TCPIP prefix.
To change the default TCPIP prefix, you may apply zap number Z5504151, which is included on the SAS software install tape and is documented in usage notes.
For example, to produce this SERVICES file
SYS.PROD.CONFIG.ETC.SERVICES
specify a TCPIP prefix of SYS.PROD.CONFIG by using the zap.
The TCPIPPRF option initializes a filename prefix for the current SAS session. Each session that uses the TCP/IP access method (SAS/CONNECT local and remote hosts and SAS/SHARE server and clients) must set this option at initialization time. For example, to produce this configuration file
SYS2.VER2.TCP.ETC.HOSTS
set the TCPIPPRF option to SYS2.VER2.TCP as follows:
sas ... options ('TCPIPPRF=SYS2.VER2.TCP')
| Redirecting Error Output with the SASCTCPE DDname |
To document the operating behavior of the SAS/C Transient Library, the SAS/C libraries write all messages (error and informational) to the SAS log, the terminal screen, or the SASCTCPE DDname to SYSOUT. The DDname of SASCTCPE is reserved to contain the redirection of library error messages.
To prevent the writing of informational and error messages to your terminal screen, you can direct SASCTCPE to DUMMY.
If you have trouble making a TCP/IP connection, you may want to direct SASCTCPE to a SYSOUT data set or to a permanent file in the local or the remote SAS execution as a troubleshooting aid.
You have completed the TCP/IP configuration process.
| Reference |
For complete details about the SAS/C Socket Library for TCP/IP, see SAS/C Library Reference, Third Edition, Volume 2, Release 6.00.
The TCP/IP access method for OS/390 is implemented with SAS/C Socket Library functions.
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Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.