Re: Active FTP PORT command - port number
- From: allab@xxxxxxxxxxxx
- Date: 28 Jan 2007 19:40:18 -0800
Barry,
The question was regarding PORT command in ACTIVE FTP mode.
In active mode FTP the client connects from a random unprivileged port
(N > 1023) to the FTP server's command port, port 21. Then, the client
starts listening to port N+1 and sends the FTP command PORT N+1 to the
FTP server. The server will then connect back to the client's
specified data port from its local data port, which is port 20.
Where does the number of a random unprivileged port come from?
Thanks,
Alona
On Jan 28, 9:42 am, Barry Margolin <bar...@xxxxxxxxxxxx> wrote:
In article <1169954472.299107.148...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
a...@xxxxxxxxxxxx wrote:
Hello All,
The PORT request has a parameter in the form
h1,h2,h3,h4,p1,p2
meaning that the client is listening for connections on TCP port
p1*256+p2 at IP address h1.h2.h3.h4.
Where p1 and p2 numbers are coming from? Are there any ftpbind the socket to it. It will change from connection to connection.
configuration files?The FTP server normally asks the stack to find an unused port number and
--
Barry Margolin, bar...@xxxxxxxxxxxx
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***
.
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- From: allab
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