LDAP directory services versus the Sybase interfaces file

The LDAP driver implements directory services for use with an LDAP server. LDAP directories are an infrastructure that provide:

Table 5-1 highlights the differences between the Sybase interfaces file and an LDAP server.

Table 5-1: interfaces file versus LDAP directory services

interfaces file

Directory services



Specific to each Sybase installation

Centralized and hierarchical

Contains separate master and query entries

One entry for each server that is accessed by both clients and servers

Cannot store metadata about the server

Stores metadata about the server

LDAP directory services support more attributes than the Sybase interfaces file. These attributes can include server version, server status, and so on. See Table 5-2 for a list of attributes.

NoteLDAP is only supported with reentrant libraries. You must use isql_r, instead of isql, when connecting to a server using LDAP directory services.

Table 5-2 lists the Sybase LDAP directory entries.

Table 5-2: Sybase LDAP directory definitions

Attribute name

Value type



interfaces file or libtcl*.cfg

DIT base for object tree. If the libtcl*.cfg file is specified, the interfaces file is ignored. The libtcl*.cfg file can be overridden with ct_con_prop() for a specified connection.


Character string

Distinguished name. Must be unique name that identifies the object.



Server version number.


Character string

Server name.


Character string

Service type: Sybase Adaptive Server, or Sybase SQL Server.



Status: 1 = Active, 2 = Stopped, 3 = Failed, 4 = Unknown.



Each server address includes:

  • Protocol: TCP, NAMEPIPE, SPX DECNET (entry is case-sensitive).

  • Address: any valid address for the protocol type.

    Notedscp splits this attribute into Transport type and Transport address.

sybaseSecurity (optional)


Security OID (object ID).



This attribute is mapped to CS_RETRY_COUNT, which specifies the number of times that ct_connect retries the sequence of network addresses associated with a server name.



This attribute is mapped to CS_LOOP_DELAY, which specifies the delay, in seconds, that ct_connect waits before retrying the entire sequence of addresses.

sybaseHAservername (optional)


A secondary server for failover protection.

The traditional interfaces file with TCP connection and a failover machine looks like:

master tcp ether huey 5000
query tcp ether huey 5000
hafailover secondary

An example of an LDAP entry with TCP and a failover machine looks like:

dn: sybaseServername=foobar, dc=sybase,dc=com
objectClass: sybaseServer
sybaseVersion: 12500
sybaseServername: foobar
sybaseService: ASE
sybaseStatus: 4
sybaseAddress: TCP#1#foobar 5000
sybaseRetryCount: 12
sybaseRetryDelay: 30
sybaseHAServernam: secondary

All entries in the LDAP directory service are called entities. Each entity has a distinguished name (DN) and is stored in a hierarchical tree structure based on its DN. This tree is call the directory information tree (DIT). Client applications use a DIT base to specify where entities are stored. See “The libtcl.cfg and libtcl64.cfg files”.

In the example above, the entry describes an Adaptive Server named “foobar” listening on a TCP connection with a port number of 5000. This entity also specifies a retry count of 12 (times) and a retry delay of 30 (seconds). Once a client has found an address where a server responds, the login dialog between the client and the server begins.

You can find a complete list of Sybase’s LDAP directory schema in NT – %SYBASE%\%SYBASE_OCS%\ini.In the same directory, there is also a file called sybase-schema.conf, which contains the same schema, but uses a Netscape-specific syntax.

Since LDAP supports multiple entries for each attribute, each address attribute must contain the address of a single server, including protocol, access type, and address. See sybaseAddress in Table 5-2.

For example, this is an LDAP entry for an NT server listening on two addresses, with different connection protocols:

sybaseAddress = TCP#1#TOEJAM 4444
sybaseAddress = NAMEPIPE#1#\pipe\sybase\query

NoteEach entry in the address field is separated by the # character.

You can edit these entries with dsedit. See “Adding a server to the directory services”.

To ensure cross-platform compatibility for all Sybase products, the protocol and address attribute fields should be in a platform- and product-independent format.