# Kamailio configuration for routing based on destination number

# Define the destination number patterns and their corresponding servers
modparam("htable", "htable", "dstroutes=>size=10;autoexpire=3600")

# Fill the hash table with destination patterns and target IPs
request_route {
    # ... other configuration ...
    
    # Check if it's an INVITE
    if (is_method("INVITE")) {
        # Extract the destination number from the Request-URI
        if ($rU =~ "^(1234.*)$") {
            # Route calls to numbers starting with 1234 to a specific server
            $du = "sip:$rU@192.168.1.10:5060";
            route(RELAY);
            exit;
        }
        
        if ($rU =~ "^(5678.*)$") {
            # Route calls to numbers starting with 5678 to another server
            $du = "sip:$rU@192.168.1.20:5060";
            route(RELAY);
            exit;
        }
        
        # Default routing if no pattern matches
        # ...
    }
    
    # ... continue with other routing logic ...
}

# Relay route
route[RELAY] {
    if (!t_relay()) {
        sl_reply_error();
    }
}