diff --git a/lib/ftp.c b/lib/ftp.c
index adb2ebd99c..e24ae9c15d 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -972,7 +972,7 @@ static CURLcode ftp_state_use_port(struct Curl_easy *data,
         if(ip_end) {
           /* either ipv6 or (ipv4|domain|interface):port(-range) */
 #ifdef ENABLE_IPV6
-          if(Curl_inet_pton(AF_INET6, string_ftpport, sa6) == 1) {
+          if(Curl_inet_pton(AF_INET6, string_ftpport, &sa6->sin6_addr) == 1) {
             /* ipv6 */
             port_min = port_max = 0;
             strcpy(addr, string_ftpport);