As reported in Mandrake's bug tracker bug 12285

bagder · bagder · commit 0966ddafaa7f · 2004-11-29T21:25:07.000Z
(http://qa.mandrakesoft.com/show_bug.cgi?id=12285), when connecting to an IPv6 host with FTP, --disable-epsv (or --disable-eprt) effectively disables the ability to transfer a file. Now, when connected to an FTP server with IPv6, these FTP commands can't be disabled even if asked to with the available libcurl options.
diff --git a/CHANGES b/CHANGES
@@ -6,6 +6,14 @@
 
                                   Changelog
 
+Daniel (29 November 2004)
+- As reported in Mandrake's bug tracker bug 12285
+  (http://qa.mandrakesoft.com/show_bug.cgi?id=12285), when connecting to an
+  IPv6 host with FTP, --disable-epsv (or --disable-eprt) effectively disables
+  the ability to transfer a file. Now, when connected to an FTP server with
+  IPv6, these FTP commands can't be disabled even if asked to with the
+  available libcurl options.
+
 Daniel (26 November 2004)
 - As reported in Mandrake's bug tracker bug 12289
   (http://qa.mandrakesoft.com/show_bug.cgi?id=12289), curl would print a
diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
@@ -21,7 +21,7 @@
 .\" * $Id$
 .\" **************************************************************************
 .\"
-.TH curl_easy_setopt 3 "21 Nov 2004" "libcurl 7.12.3" "libcurl Manual"
+.TH curl_easy_setopt 3 "29 Nov 2004" "libcurl 7.12.3" "libcurl Manual"
 .SH NAME
 curl_easy_setopt - set options for a curl easy handle
 .SH SYNOPSIS
@@ -706,11 +706,15 @@ LPRT) command when doing active FTP downloads (which is enabled by
 \fICURLOPT_FTPPORT\fP). Using EPRT means that it will first attempt to use
 EPRT and then LPRT before using PORT, but if you pass FALSE (zero) to this
 option, it will not try using EPRT or LPRT, only plain PORT. (Added in 7.10.5)
+
+If the server is an IPv6 host, this option will have no effect as of 7.12.3.
 .IP CURLOPT_FTP_USE_EPSV
 Pass a long. If the value is non-zero, it tells curl to use the EPSV command
 when doing passive FTP downloads (which it always does by default). Using EPSV
 means that it will first attempt to use EPSV before using PASV, but if you
 pass FALSE (zero) to this option, it will not try using EPSV, only plain PASV.
+
+If the server is an IPv6 host, this option will have no effect as of 7.12.3.
 .IP CURLOPT_FTP_CREATE_MISSING_DIRS
 Pass a long. If the value is non-zero, curl will attempt to create any remote
 directory that it fails to CWD into. CWD is the command that changes working
diff --git a/lib/ftp.c b/lib/ftp.c
@@ -1184,6 +1184,16 @@ CURLcode ftp_use_port(struct connectdata *conn)
     return CURLE_FTP_PORT_FAILED;
   }
 
+#ifdef PF_INET6
+  if(!conn->bits.ftp_use_eprt &&
+     (conn->ip_addr->ai_family == PF_INET6)) {
+    /* EPRT is disabled but we are connected to a IPv6 host, so we ignore the
+       request! */
+    conn->bits.ftp_use_eprt = TRUE;
+  }
+#endif
+
+
   for (fcmd = EPRT; fcmd != DONE; fcmd++) {
     int lprtaf, eprtaf;
     int alen=0, plen=0;
@@ -1512,6 +1522,15 @@ CURLcode ftp_use_pasv(struct connectdata *conn,
   char newhost[48];
   char *newhostp=NULL;
 
+#ifdef PF_INET6
+  if(!conn->bits.ftp_use_epsv &&
+     (conn->ip_addr->ai_family == PF_INET6)) {
+    /* EPSV is disabled but we are connected to a IPv6 host, so we ignore the
+       request! */
+    conn->bits.ftp_use_epsv = TRUE;
+  }
+#endif
+
   for (modeoff = (conn->bits.ftp_use_epsv?0:1);
        mode[modeoff]; modeoff++) {
     result = Curl_ftpsendf(conn, "%s", mode[modeoff]);
