These are parameters that can be defined by the writer of kamailio.cfg in order to be used inside routing blocks. One of the important properties for custom global parameters is that their value can be changed at runtime via RPC commands, without restarting Kamailio.
The definition of a custom global parameter must follow the pattern:
group.variable = value desc "description"
The value can be a quoted string or integer number.
Example:
pstn.gw_ip = "1.2.3.4" desc "PSTN GW Address"
The custom global parameter can be accessed inside a routing block via:
$sel(cfg_get.group.variable)
Example:
$ru = "sip:" + $rU + "@" + $sel(cfg_get.pstn.gw_ip);
Note: Some words cannot be used as (part of) names for custom variables or groups, and if they are used a syntax error is logged by kamailio. These keywords are: “yes”, “true”, “on”, “enable”, “no”, “false”, “off”, “disable”, “udp”, “UDP”, “tcp”, “TCP”, “tls”, “TLS”, “sctp”, “SCTP”, “ws”, “WS”, “wss”, “WSS”, “inet”, “INET”, “inet6”, “INET6”, “sslv23”, “SSLv23”, “SSLV23”, “sslv2”, “SSLv2”, “SSLV2”, “sslv3”, “SSLv3”, “SSLV3”, “tlsv1”, “TLSv1”, “TLSV1”