clarified the FTP passive/active mode options somewhat

diff --git a/docs/curl.1 b/docs/curl.1
index 72cff8229ea930e451b760a7b05dfe14b306e3e8..fab00f3dd1b6f7a0c2f7ee614bc8d4b01f70a4ef 100644 (file)
--- a/docs/curl.1
+++ b/docs/curl.1
@@ -292,6 +292,10 @@ traditional PORT command.
 
 Since curl 7.19.0, \fB--eprt\fP can be used to explicitly enable EPRT again
 and \fB--no-eprt\fP is an alias for \fB--disable-eprt\fP.
+
+Disabling EPRT only changes the active behavior. If you want to switch to
+passive mode you need to not use \fI-P/--ftp-port\fP or force it with
+\fI--ftp-pasv\fP.
 .IP "--disable-epsv"
 (FTP) Tell curl to disable the use of the EPSV command when doing passive FTP
 transfers. Curl will normally always first attempt to use EPSV before PASV,
@@ -299,6 +303,9 @@ but with this option, it will not try using EPSV.
 
 Since curl 7.19.0, \fB--epsv\fP can be used to explicitly enable EPRT again
 and \fB--no-epsv\fP is an alias for \fB--disable-epsv\fP.
+
+Disabling EPSV only changes the passive behavior. If you want to switch to
+active mode you need to use \fI-P/--ftp-port\fP.
 .IP "-D/--dump-header <file>"
 Write the protocol headers to the specified file.
 
@@ -421,13 +428,16 @@ compliant than 'nocwd' but without the full penalty of 'multicwd'.
 .RE
 (Added in 7.15.1)
 .IP "--ftp-pasv"
-(FTP) Use PASV when transferring. PASV is the internal default behavior, but
-using this option can be used to override a previous --ftp-port option. (Added
-in 7.11.0)
+(FTP) Use passive mode for the data conection. Passive is the internal default
+behavior, but using this option can be used to override a previous
+\fI-P/-ftp-port\fP option. (Added in 7.11.0)
 
 If this option is used several times, the following occurrences make no
-difference. Undoing an enforced PASV really isn't doable but you must then
-instead enforce the correct EPRT again.
+difference. Undoing an enforced passive really isn't doable but you must then
+instead enforce the correct \fI-P/--ftp-port\fP again.
+
+Passive mode means that curl will try the EPSV command first and then PASV,
+unless \fI--disable-epsv\fP is used.
 .IP "--ftp-alternative-to-user <command>"
 (FTP) If authenticating with the USER and PASS commands fails, send this
 command.  When connecting to Tumbleweed's Secure Transport server over FTPS
@@ -922,11 +932,11 @@ separate file.
 
 If this option is used several times, the last one will be used.
 .IP "-P/--ftp-port <address>"
-(FTP) Reverses the initiator/listener roles when connecting with FTP. This
-switch makes Curl use the PORT command instead of PASV. In practice, PORT
-tells the server to connect to the client's specified address and port, while
-PASV asks the server for an IP address and port to connect to. <address>
-should be one of:
+(FTP) Reverses the default initiator/listener roles when connecting with
+FTP. This switch makes curl use active mode. In practice, curl then tells the
+server to connect back to the client's specified address and port, while
+passive mode asks the server to setup an IP address and port for it to connect
+to. <address> should be one of:
 .RS
 .IP interface
 i.e "eth0" to specify which interface's IP address you want to use (Unix only)