SFTP

May 20, 2008
9,537
64
Syracuse, NY, USA
More info. I don't think this is correct behavior. Here's the TCC end of three connections.
Code:
v:\> iftp sftp://vefatica.net
TCC: Cannot authenticate with provided credentials. The following authentication methods are available for this user: password,publickey. "vefatica.net"
v:\> iftp /c

v:\> iftp sftp://rexconn:*************@vefatica.net
v:\> iftp /c

v:\> iftp sftp://vefatica.net
v:\> iftp /c
Below are the server's logs. In the first connection (000058) TCC apparently sends an empty username and the connection fails. In any given TCC session, that will always fail until a successful connection is made. The second connection (000059), by rexconn, succeeds. The third connection (000060), meant to be anonymous, succeeds but logs in the user rexconn.

Code:
[02] Fri 10Nov17 12:28:09 - (000058) Connected to 72.230.84.150 (local address 72.230.84.150, port 22)
[03] Fri 10Nov17 12:28:09 - (000058) IP-Name: zz.twcny.rr.com (72.230.84.150)
[30] Fri 10Nov17 12:28:09 - (000058) SSH2_MSG_USERAUTH_REQUEST: user: ; service: ssh-connection; type: none
[02] Fri 10Nov17 12:28:09 - (000058) Invalid login credentials; user: ""; password: "**********"
[31] Fri 10Nov17 12:28:09 - (000058) SSH2_MSG_USERAUTH_FAILURE: login failed
[02] Fri 10Nov17 12:28:09 - (000058) Closed session

[02] Fri 10Nov17 12:28:24 - (000059) Connected to 72.230.84.150 (local address 72.230.84.150, port 22)
[03] Fri 10Nov17 12:28:24 - (000059) IP-Name: zz.twcny.rr.com (72.230.84.150)
[30] Fri 10Nov17 12:28:25 - (000059) SSH2_MSG_USERAUTH_REQUEST: user: rexconn; service: ssh-connection; type: none
[31] Fri 10Nov17 12:28:25 - (000059) SSH2_MSG_USERAUTH_FAILURE: login failed
[30] Fri 10Nov17 12:28:25 - (000059) SSH2_MSG_USERAUTH_REQUEST: user: rexconn; service: ssh-connection; type: password
[02] Fri 10Nov17 12:28:25 - (000059) User "rexconn" logged in
[31] Fri 10Nov17 12:28:25 - (000059) SSH2_MSG_USERAUTH_SUCCESS: successful login
[30] Fri 10Nov17 12:28:25 - (000059) SSH_FXP_INIT: client version 3 (IP*Works! SSH Client 2016)
[31] Fri 10Nov17 12:28:25 - (000059) SSH_FXP_VERSION: server version 3
[30] Fri 10Nov17 12:28:25 - (000059) {0x00000001} SSH_FXP_REALPATH: path: "."
[31] Fri 10Nov17 12:28:25 - (000059) {0x00000001} SSH_FXP_NAME: path: "/"
[30] Fri 10Nov17 12:28:34 - (000059) {0x00000002} SSH_FXP_REALPATH: path: "/"
[31] Fri 10Nov17 12:28:34 - (000059) {0x00000002} SSH_FXP_NAME: path: "/"
[02] Fri 10Nov17 12:28:34 - (000059) Closed session
[02] Fri 10Nov17 12:28:34 - (000059) User "rexconn" logged out

[02] Fri 10Nov17 12:28:43 - (000060) Connected to 72.230.84.150 (local address 72.230.84.150, port 22)
[03] Fri 10Nov17 12:28:43 - (000060) IP-Name: zz.twcny.rr.com (72.230.84.150)
[30] Fri 10Nov17 12:28:43 - (000060) SSH2_MSG_USERAUTH_REQUEST: user: rexconn; service: ssh-connection; type: none
[31] Fri 10Nov17 12:28:43 - (000060) SSH2_MSG_USERAUTH_FAILURE: login failed
[30] Fri 10Nov17 12:28:43 - (000060) SSH2_MSG_USERAUTH_REQUEST: user: rexconn; service: ssh-connection; type: password
[02] Fri 10Nov17 12:28:43 - (000060) User "rexconn" logged in
[31] Fri 10Nov17 12:28:43 - (000060) SSH2_MSG_USERAUTH_SUCCESS: successful login
[30] Fri 10Nov17 12:28:43 - (000060) SSH_FXP_INIT: client version 3 (IP*Works! SSH Client 2016)
[31] Fri 10Nov17 12:28:43 - (000060) SSH_FXP_VERSION: server version 3
[30] Fri 10Nov17 12:28:43 - (000060) {0x00000001} SSH_FXP_REALPATH: path: "/"
[31] Fri 10Nov17 12:28:43 - (000060) {0x00000001} SSH_FXP_NAME: path: "/"
[30] Fri 10Nov17 12:28:48 - (000060) {0x00000002} SSH_FXP_REALPATH: path: "/"
[31] Fri 10Nov17 12:28:48 - (000060) {0x00000002} SSH_FXP_NAME: path: "/"
[02] Fri 10Nov17 12:28:48 - (000060) Closed session
[02] Fri 10Nov17 12:28:48 - (000060) User "rexconn" logged out
Here's the log of the same three connections with FTP (instead of SFTP). It shows three logins ... anonymous, rexconn, and anonymous. It seems better.
Code:
[20] Fri 10Nov17 12:45:01 - (000064) PASS **********
[02] Fri 10Nov17 12:45:01 - (000064) ANONYMOUS logged in, password: JPUser@
[21] Fri 10Nov17 12:45:01 - (000064) 230 User logged in, proceed.
[20] Fri 10Nov17 12:45:01 - (000064) PWD
[21] Fri 10Nov17 12:45:01 - (000064) 257 "/" is current directory.
[20] Fri 10Nov17 12:45:14 - (000064) QUIT
[21] Fri 10Nov17 12:45:14 - (000064) 221 Goodbye, closing session.
[02] Fri 10Nov17 12:45:14 - (000064) User "anonymous" logged out
[02] Fri 10Nov17 12:45:14 - (000064) Closed session

[02] Fri 10Nov17 12:45:24 - (000065) Connected to 72.230.84.150 (local address 72.230.84.150, port 21)
[03] Fri 10Nov17 12:45:24 - (000065) IP-Name: zz.twcny.rr.com (72.230.84.150)
[21] Fri 10Nov17 12:45:24 - (000065) 220 Serv-U FTP Server v14.0 ready...
[20] Fri 10Nov17 12:45:24 - (000065) USER rexconn
[21] Fri 10Nov17 12:45:24 - (000065) 331 User name okay, need password.
[20] Fri 10Nov17 12:45:24 - (000065) PASS **********
[02] Fri 10Nov17 12:45:24 - (000065) User "rexconn" logged in
[21] Fri 10Nov17 12:45:24 - (000065) 230 User logged in, proceed.
[20] Fri 10Nov17 12:45:24 - (000065) PWD
[21] Fri 10Nov17 12:45:24 - (000065) 257 "/" is current directory.
[20] Fri 10Nov17 12:45:32 - (000065) QUIT
[21] Fri 10Nov17 12:45:32 - (000065) 221 Goodbye, closing session.
[02] Fri 10Nov17 12:45:32 - (000065) User "rexconn" logged out
[02] Fri 10Nov17 12:45:32 - (000065) Closed session

[02] Fri 10Nov17 12:45:39 - (000066) Connected to 72.230.84.150 (local address 72.230.84.150, port 21)
[03] Fri 10Nov17 12:45:39 - (000066) IP-Name: zz.twcny.rr.com (72.230.84.150)
[21] Fri 10Nov17 12:45:39 - (000066) 220 Serv-U FTP Server v14.0 ready...
[20] Fri 10Nov17 12:45:39 - (000066) USER anonymous
[21] Fri 10Nov17 12:45:39 - (000066) 331 User name okay, please send complete E-mail address as password.
[20] Fri 10Nov17 12:45:39 - (000066) PASS **********
[02] Fri 10Nov17 12:45:39 - (000066) ANONYMOUS logged in, password: JPUser@
[21] Fri 10Nov17 12:45:39 - (000066) 230 User logged in, proceed.
[20] Fri 10Nov17 12:45:39 - (000066) PWD
[21] Fri 10Nov17 12:45:39 - (000066) 257 "/" is current directory.
[20] Fri 10Nov17 12:45:47 - (000066) QUIT
[21] Fri 10Nov17 12:45:47 - (000066) 221 Goodbye, closing session.
[02] Fri 10Nov17 12:45:47 - (000066) User "anonymous" logged out
[02] Fri 10Nov17 12:45:47 - (000066) Closed session
 

rconn

Administrator
Staff member
May 14, 2008
11,107
99
All WAD.

You apparently have the misconception that SSH (SFTP) has anything at all in common with FTP or FTPS. It does not; there isn't a single line of shared code between them (and SSH is using a different library). They behave differently because they are different.

TCC's SSH / SFTP does not allow anonymous logins. Most SSH servers don't allow it either, and enabling it requires some server configuration. (I don't know why anybody would even *want* to allow anonymous SSH.) That error message is actually coming from your server, so you apparently haven't enabled it. (My recommendation: don't!)

The reason the third login succeeds (without specifying the username) is a TCC feature -- it assumes that if you didn't enter a user / password, then you must want to (re)connect using the last successful username / password.

TCC has been behaving this way for about the last 14 years.