For the sake and sanity of the user of this software, we need to cover the basic elements of the configuration before getting to the meat and potatoes.

• Configuration Directives
• Comments
• Instruction Separator

There are five (5) types of configuration directives used with Kamailio.

1. C-Style Control Directives
2. Apache Name/Value Pairs
3. Normal Name/Value Pairs
4. Modify Parameter Procedure
5. Route Functions

Configuration file comments are PHP style, without the double-slash line comment. Only hash (#) will work for line comments.
This gets confusing since the hash-bang (#!) is used at the beginning of the C-Style Control Directives.

/* block comment
   block comment */
// this is NOT a line comment
# this is a line comment
#!c_style_directive

The semicolon works with all forms of configuration directives as an instruction separator. Allowing for comments or additional configuration directives on the same line.

configuration_directive_a; configuration_directive_b
configuration_directive; # comment about the configuration directive

Available directives:

• #!define NAME - define a keyword
• #!define NAME VALUE - define a keyword with value
• #!ifdef NAME - check if a keyword is defined
• #!ifndef - check if a keyword is not defined
• #!else - swtich to false branch of ifdef/ifndef region
• #!endif - end ifdef/ifndef region
• #!trydef - add a define if not already defined
• #!redefine - force redefinition even if already defined
• #!subst
• #!substdef

#!define MODULE_NAME

#!ifdef MODULE_NAME
 .. set directives ..
#!else
 .. set alternate directives .. 
#!endif

name "value"

The value MUST be enclosed in quotes.

loadmodule "module_name.so"
loadmodule "another_module.so"
include_file "file_to_include.cfg"
import_file "/path/to/file_to_import.cfg"

name=value

(delimited by an equals sign)

core_parameters

memdbg=5
memlog=5
log_facility=LOG_LOCAL0
fork=yes
children=4
#disable_tcp=yes
auto_aliases=no
alias="sip.mydomain.com"

modparam("first_module", "module_parameter_text", "new_value");  # Set Text Value
modparam("second_module", "module_parameter_number", 10000);      # Set Numeric Value
modparam("second_module", "module_parameter_on", 1);              # Enable Parameter
modparam("third_module", "module_parameter_on", 0);             # Disable Parameter