diff --git a/src/first-free-port.c b/src/first-free-port.c
index 35005dc..320b14e 100644
--- a/src/first-free-port.c
+++ b/src/first-free-port.c
@@ -23,7 +23,8 @@ static void print_error(char *name, const char *message) {
 /**
  * Get all the listening TCP ports
  */
-static unsigned short *get_listening_ports(unsigned short *listening_ports, FILE *tcp_table_fptr) {
+static unsigned short *get_listening_ports(FILE *tcp_table_fptr) {
+    unsigned short *listening_ports = malloc(BLOCKS_TO_ALLOC * sizeof(short));
     char line[TCP_TABLE_LINE_LENGTH];
     char delimiter[] = " ";
     unsigned short len = 0;
@@ -99,8 +100,7 @@ int main(int argc, char *argv[]) {
         return errno;
     }
 
-    unsigned short *listening_ports = malloc(PORTS_BLOCKS_TO_ALLOW * sizeof(unsigned short));
-    listening_ports = get_listening_ports(listening_ports, tcp_table_fptr);
+    unsigned short *listening_ports = get_listening_ports(tcp_table_fptr);
 
     if (fclose(tcp_table_fptr) != 0) {
         print_error(argv[0], "can't close the TCP table.");