3 Syntax Rules for Configuration Files

This chapter describes the syntax rules for Oracle Net Services configuration files.

This chapter contains these topics:

Configuration File Syntax Overview

The Oracle Net Services configuration files consist of parameters which include keyword-value pairs. Keyword-value pairs are surrounded by parentheses:


Some keywords have other keyword-value pairs as their values:


For example, the address portion of a local naming configuration file (tnsnames.ora) might include the following lines:


Set up configuration files so that indentation reflects what keyword is the parent or owner of other keyword-value pairs.

Even if you do not choose to indent your files in this way, you must indent a wrapped line by at least one space, or it will be misread as a new parameter. The following layout is acceptable:


The following layout is not acceptable:


Further Syntax Rules for Configuration Files

The following rules apply to the syntax of configuration files:

  • Any keyword in a configuration file that begins a parameter that includes one or more keyword-value pairs must be in the far left column of a line. If it is indented by one or more spaces, it is interpreted as a continuation of the previous line.

  • All characters must belong to the network character set

  • Keywords are not case sensitive. Values may be case sensitive, depending on the operating system and protocol.

  • Spaces around the "=" sign are optional in keyword-value pairs.

  • There is a hierarchy of keywords in that some keywords are always followed by others. At any level of the hierarchy, keywords can be listed in any order. For example, the following entries are equally valid:

  • Keywords cannot contain spaces. Values must not contain spaces unless enclosed within double quotes (") or single quotes (').

  • The maximum length of a connect descriptor is 4 KB

  • Comments can be included using the pound sign # at the beginning of a line. Anything following the sign to the end of the line is considered a comment.

  • If the keyword-value pair consists of a single word or a concatenation of words on either side of the equal sign, no parentheses are needed.

Network Character Set

The network character set for keyword values consists of the following characters. Connect descriptors must be made up of single-byte characters.

A-Z, a-z


( ) < > / \

, . : ; ' "=- _

$ + * # & ! % ? @

Within this character set, the following symbols are reserved:

( )=\ " ' #

Reserved symbols are used as delimiters, not as part of a keyword or a value unless the keyword or value is quoted. Either single or double quotes can be used to enclose a value containing reserved symbols. To include a quote within a value that is surrounded by quotes, use different quote types. The backslash (\) is used as an escape character.

The following characters may be used within a connect descriptor, but not in a keyword or value:

<Space> <Tab> <Carriage Return> <Newline>

Character Set

The listener name and net service name are limited to the following character set:

[a...z] [A...Z] [0...9] _

The first character must be an alphabetical character. In general, up to 64 characters is acceptable. A database service name must match the global database name defined by the database administrator, which consists of a database name (originally limited to eight characters), and the database domain. Net service names and global database names are not case sensitive.