It would be possible. But to be honest, improving SCP fallback now, when SCP is falling into obscurity, is a waste of a time, imho.

martin wrote:

The fallback does not work if the SSH server closes the connection instead of just refusing to start SFTP.

would it be possible to have WinSCP re-try the connection in that case?

The fallback does not work if the SSH server closes the connection instead of just refusing to start SFTP.

it doesn't work for me. but forced SCP works fine.

SCP fallback:



. 2012-01-21 01:21:01.631 --------------------------------------------------------------------------
. 2012-01-21 01:21:01.631 WinSCP Version 5.0.5 (Build 1782) (OS 6.1.7601 Service Pack 1)
. 2012-01-21 01:21:01.632 Configuration: E:\bin\WinSCP.ini
. 2012-01-21 01:21:01.633 Local account: DOMAIN\user
. 2012-01-21 01:21:01.633 Login time: Saturday, January 21, 2012 1:21:01 AM
. 2012-01-21 01:21:01.633 --------------------------------------------------------------------------
. 2012-01-21 01:21:01.633 Session name: user@10.0.0.1 (Modified stored session)
. 2012-01-21 01:21:01.633 Host name: 10.0.0.1 (Port: 22)
. 2012-01-21 01:21:01.633 User name: user (Password: No, Key file: Yes)
. 2012-01-21 01:21:01.633 Tunnel: No
. 2012-01-21 01:21:01.633 Transfer Protocol: SFTP (SCP)
. 2012-01-21 01:21:01.633 Ping type: -, Ping interval: 30 sec; Timeout: 15 sec
. 2012-01-21 01:21:01.633 Proxy: none
. 2012-01-21 01:21:01.633 SSH protocol version: 2; Compression: No
. 2012-01-21 01:21:01.633 Bypass authentication: No
. 2012-01-21 01:21:01.633 Try agent: Yes; Agent forwarding: No; TIS/CryptoCard: No; KI: Yes; GSSAPI: No
. 2012-01-21 01:21:01.633 Ciphers: aes,blowfish,3des,WARN,arcfour,des; Ssh2DES: No
. 2012-01-21 01:21:01.633 SSH Bugs: -,-,-,-,-,-,-,-,-
. 2012-01-21 01:21:01.633 SFTP Bugs: -,-
. 2012-01-21 01:21:01.633 Return code variable: Autodetect; Lookup user groups: Yes
. 2012-01-21 01:21:01.633 Shell: default
. 2012-01-21 01:21:01.633 EOL: 0, UTF: 2
. 2012-01-21 01:21:01.633 Clear aliases: Yes, Unset nat.vars: Yes, Resolve symlinks: Yes
. 2012-01-21 01:21:01.633 LS: ls -la, Ign LS warn: Yes, Scp1 Comp: No
. 2012-01-21 01:21:01.633 Local directory: default, Remote directory: home, Update: No, Cache: Yes
. 2012-01-21 01:21:01.633 Cache directory changes: Yes, Permanent: Yes
. 2012-01-21 01:21:01.633 DST mode: 1
. 2012-01-21 01:21:01.633 --------------------------------------------------------------------------
. 2012-01-21 01:21:01.728 Looking up host "10.0.0.1"
. 2012-01-21 01:21:01.728 Connecting to 10.0.0.1 port 22
. 2012-01-21 01:21:01.780 Server version: SSH-2.0-dropbear_0.52
. 2012-01-21 01:21:01.780 We believe remote version has SSH-2 ignore bug
. 2012-01-21 01:21:01.780 Using SSH protocol version 2
. 2012-01-21 01:21:01.780 We claim version: SSH-2.0-WinSCP_release_5.0.5
. 2012-01-21 01:21:01.787 Using Diffie-Hellman with standard group "group1"
. 2012-01-21 01:21:01.787 Doing Diffie-Hellman key exchange with hash SHA-1
. 2012-01-21 01:21:02.884 Host key fingerprint is:
. 2012-01-21 01:21:02.884 ssh-rsa 1040 31:58:74:6a:4b:c5:91:5b:b7:c4:42:69:ac:2b:b7:51
. 2012-01-21 01:21:02.884 Initialised AES-256 SDCTR client->server encryption
. 2012-01-21 01:21:02.884 Initialised HMAC-SHA1 client->server MAC algorithm
. 2012-01-21 01:21:02.884 Initialised AES-256 SDCTR server->client encryption
. 2012-01-21 01:21:02.884 Initialised HMAC-SHA1 server->client MAC algorithm
. 2012-01-21 01:21:02.890 Reading private key file "C:\Users\user\putty.ppk"
! 2012-01-21 01:21:02.891 Using username "user".
. 2012-01-21 01:21:02.939 Offered public key
. 2012-01-21 01:21:02.944 Offer of public key accepted
! 2012-01-21 01:21:02.944 Authenticating with public key "rsa-key-20110106"
. 2012-01-21 01:21:03.028 Access granted
. 2012-01-21 01:21:03.030 Opened channel for session
. 2012-01-21 01:21:03.073 Started a shell/command
. 2012-01-21 01:21:03.094 --------------------------------------------------------------------------
. 2012-01-21 01:21:03.095 Using SFTP protocol.
. 2012-01-21 01:21:03.096 Doing startup conversation with host.
> 2012-01-21 01:21:03.146 Type: SSH_FXP_INIT, Size: 5, Number: -1
! 2012-01-21 01:21:03.146 sh: /opt/libexec/sftp-server: not found
. 2012-01-21 01:21:03.146 Server sent command exit status 127
. 2012-01-21 01:21:03.146 Disconnected: All channels closed
* 2012-01-21 01:21:03.208 (EFatal) Connection has been unexpectedly closed. Server sent command exit status 127.
* 2012-01-21 01:21:03.208 Cannot initialize SFTP protocol. Is the host running a SFTP server?


forced SCP:

. 2012-01-21 01:26:11.475 --------------------------------------------------------------------------
. 2012-01-21 01:26:11.476 WinSCP Version 5.0.5 (Build 1782) (OS 6.1.7601 Service Pack 1)
. 2012-01-21 01:26:11.476 Configuration: E:\bin\WinSCP.ini
. 2012-01-21 01:26:11.477 Local account: DOMAIN\user
. 2012-01-21 01:26:11.477 Login time: Saturday, January 21, 2012 1:26:11 AM
. 2012-01-21 01:26:11.477 --------------------------------------------------------------------------
. 2012-01-21 01:26:11.477 Session name: user@10.0.0.1 (Modified stored session)
. 2012-01-21 01:26:11.477 Host name: 10.0.0.1 (Port: 22)
. 2012-01-21 01:26:11.477 User name: user (Password: No, Key file: Yes)
. 2012-01-21 01:26:11.477 Tunnel: No
. 2012-01-21 01:26:11.477 Transfer Protocol: SCP
. 2012-01-21 01:26:11.477 Ping type: -, Ping interval: 30 sec; Timeout: 15 sec
. 2012-01-21 01:26:11.477 Proxy: none
. 2012-01-21 01:26:11.477 SSH protocol version: 2; Compression: No
. 2012-01-21 01:26:11.477 Bypass authentication: No
. 2012-01-21 01:26:11.477 Try agent: Yes; Agent forwarding: No; TIS/CryptoCard: No; KI: Yes; GSSAPI: No
. 2012-01-21 01:26:11.477 Ciphers: aes,blowfish,3des,WARN,arcfour,des; Ssh2DES: No
. 2012-01-21 01:26:11.477 SSH Bugs: -,-,-,-,-,-,-,-,-
. 2012-01-21 01:26:11.477 SFTP Bugs: -,-
. 2012-01-21 01:26:11.477 Return code variable: Autodetect; Lookup user groups: Yes
. 2012-01-21 01:26:11.477 Shell: default
. 2012-01-21 01:26:11.477 EOL: 0, UTF: 2
. 2012-01-21 01:26:11.477 Clear aliases: Yes, Unset nat.vars: Yes, Resolve symlinks: Yes
. 2012-01-21 01:26:11.477 LS: ls -la, Ign LS warn: Yes, Scp1 Comp: No
. 2012-01-21 01:26:11.477 Local directory: default, Remote directory: home, Update: No, Cache: Yes
. 2012-01-21 01:26:11.477 Cache directory changes: Yes, Permanent: Yes
. 2012-01-21 01:26:11.477 DST mode: 1
. 2012-01-21 01:26:11.477 --------------------------------------------------------------------------
. 2012-01-21 01:26:11.572 Looking up host "10.0.0.1"
. 2012-01-21 01:26:11.572 Connecting to 10.0.0.1 port 22
. 2012-01-21 01:26:11.624 Server version: SSH-2.0-dropbear_0.52
. 2012-01-21 01:26:11.624 We believe remote version has SSH-2 ignore bug
. 2012-01-21 01:26:11.624 Using SSH protocol version 2
. 2012-01-21 01:26:11.624 We claim version: SSH-2.0-WinSCP_release_5.0.5
. 2012-01-21 01:26:11.630 Using Diffie-Hellman with standard group "group1"
. 2012-01-21 01:26:11.630 Doing Diffie-Hellman key exchange with hash SHA-1
. 2012-01-21 01:26:12.726 Host key fingerprint is:
. 2012-01-21 01:26:12.726 ssh-rsa 1040 31:58:74:6a:4b:c5:91:5b:b7:c4:42:69:ac:2b:b7:52
. 2012-01-21 01:26:12.726 Initialised AES-256 SDCTR client->server encryption
. 2012-01-21 01:26:12.726 Initialised HMAC-SHA1 client->server MAC algorithm
. 2012-01-21 01:26:12.726 Initialised AES-256 SDCTR server->client encryption
. 2012-01-21 01:26:12.726 Initialised HMAC-SHA1 server->client MAC algorithm
. 2012-01-21 01:26:12.732 Reading private key file "C:\Users\user\putty.ppk"
! 2012-01-21 01:26:12.732 Using username "user".
. 2012-01-21 01:26:12.781 Offered public key
. 2012-01-21 01:26:12.786 Offer of public key accepted
! 2012-01-21 01:26:12.786 Authenticating with public key "rsa-key-20110106"
. 2012-01-21 01:26:12.870 Access granted
. 2012-01-21 01:26:12.873 Opened channel for session
. 2012-01-21 01:26:12.910 Started a shell/command
. 2012-01-21 01:26:12.936 --------------------------------------------------------------------------
. 2012-01-21 01:26:12.936 Using SCP protocol.
. 2012-01-21 01:26:12.937 Doing startup conversation with host.
. 2012-01-21 01:26:12.988 Skipping host startup message (if any).
> 2012-01-21 01:26:12.988 echo "WinSCP: this is end-of-file:0"
< 2012-01-21 01:26:13.045 WinSCP: this is end-of-file:0
. 2012-01-21 01:26:13.045 Detecting variable containing return code of last command.
. 2012-01-21 01:26:13.046 Trying "$status".
> 2012-01-21 01:26:13.046 echo "$status" ; echo "WinSCP: this is end-of-file:0"
< 2012-01-21 01:26:13.124 WinSCP: this is end-of-file:0
. 2012-01-21 01:26:13.125 The response is not numerical exit code
. 2012-01-21 01:26:13.125 Trying "$?".
> 2012-01-21 01:26:13.125 echo "$?" ; echo "WinSCP: this is end-of-file:0"
< 2012-01-21 01:26:13.186 0
< 2012-01-21 01:26:13.207 WinSCP: this is end-of-file:0
. 2012-01-21 01:26:13.208 Return code variable "$?" selected.
. 2012-01-21 01:26:13.208 Clearing all aliases.
> 2012-01-21 01:26:13.208 unalias "ls" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.250 unalias: ls not found
< 2012-01-21 01:26:13.267 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.267 unalias "echo" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.310 unalias: echo not found
< 2012-01-21 01:26:13.328 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.328 unalias "pwd" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.370 unalias: pwd not found
< 2012-01-21 01:26:13.387 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.387 unalias "cd" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.430 unalias: cd not found
< 2012-01-21 01:26:13.447 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.447 unalias "groups" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.493 unalias: groups not found
< 2012-01-21 01:26:13.512 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.512 unalias "scp" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.553 unalias: scp not found
< 2012-01-21 01:26:13.572 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.572 unalias "rm" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.610 unalias: rm not found
< 2012-01-21 01:26:13.628 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.628 unalias "mv" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.670 unalias: mv not found
< 2012-01-21 01:26:13.687 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.687 unalias "mkdir" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.733 unalias: mkdir not found
< 2012-01-21 01:26:13.752 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.752 unalias "chmod" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.793 unalias: chmod not found
< 2012-01-21 01:26:13.812 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.812 unalias "chgrp" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.850 unalias: chgrp not found
< 2012-01-21 01:26:13.867 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.867 unalias "chown" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.910 unalias: chown not found
< 2012-01-21 01:26:13.927 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.928 unalias "unset" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:13.973 unalias: unset not found
< 2012-01-21 01:26:13.992 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:13.992 unalias "unalias" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:14.033 unalias: unalias not found
< 2012-01-21 01:26:14.052 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:14.052 unalias "ln" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:14.093 unalias: ln not found
< 2012-01-21 01:26:14.111 WinSCP: this is end-of-file:1
> 2012-01-21 01:26:14.112 unalias "cp" ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:14.150 unalias: cp not found
< 2012-01-21 01:26:14.167 WinSCP: this is end-of-file:1
. 2012-01-21 01:26:14.167 Clearing national user variables.
> 2012-01-21 01:26:14.167 unset "LANG" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.226 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.226 unset "LANGUAGE" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.286 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.286 unset "LC_CTYPE" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.346 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.346 unset "LC_COLLATE" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.406 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.406 unset "LC_MONETARY" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.466 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.466 unset "LC_NUMERIC" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.526 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.526 unset "LC_TIME" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.586 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.586 unset "LC_MESSAGES" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.646 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.646 unset "LC_ALL" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.706 WinSCP: this is end-of-file:0
> 2012-01-21 01:26:14.706 unset "HUMAN_BLOCKS" ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:14.766 WinSCP: this is end-of-file:0
. 2012-01-21 01:26:14.766 Looking up groups and users.
> 2012-01-21 01:26:14.766 groups ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:14.812 -sh: groups: not found
< 2012-01-21 01:26:14.829 WinSCP: this is end-of-file:127
* 2012-01-21 01:26:14.829 (ECommand) Error looking up user groups.
* 2012-01-21 01:26:14.829 Command 'groups'
* 2012-01-21 01:26:14.829 failed with return code 127 and error message
* 2012-01-21 01:26:14.829 -sh: groups: not found.
. 2012-01-21 01:26:16.989 Getting current directory name.
> 2012-01-21 01:26:16.989 pwd ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:17.030 /tmp/home/user
< 2012-01-21 01:26:17.047 WinSCP: this is end-of-file:0
. 2012-01-21 01:26:17.047 Listing current directory.
> 2012-01-21 01:26:17.047 ls -la --full-time ; echo "WinSCP: this is end-of-file:$?"
! 2012-01-21 01:26:17.110 ls: unrecognized option `--full-time'
! 2012-01-21 01:26:17.113 BusyBox v1.17.4 (2010-11-30 19:38:45 EST) multi-call binary.
! 2012-01-21 01:26:17.121 Usage: ls [-1AacCdeFilnpLRrSsTtuvwxXhk] [FILE]...
< 2012-01-21 01:26:17.141 WinSCP: this is end-of-file:1
* 2012-01-21 01:26:17.141 (ETerminal) Command 'ls -la --full-time'
* 2012-01-21 01:26:17.141 failed with return code 1 and error message
* 2012-01-21 01:26:17.141 ls: unrecognized option `--full-time'
* 2012-01-21 01:26:17.141 BusyBox v1.17.4 (2010-11-30 19:38:45 EST) multi-call binary.
* 2012-01-21 01:26:17.141
* 2012-01-21 01:26:17.141 Usage: ls [-1AacCdeFilnpLRrSsTtuvwxXhk] [FILE]....
. 2012-01-21 01:26:17.141 Directory listing with --full-time failed, try again regular listing.
. 2012-01-21 01:26:17.141 Listing current directory.
> 2012-01-21 01:26:17.141 ls -la ; echo "WinSCP: this is end-of-file:$?"
< 2012-01-21 01:26:17.203 drwx------ 3 user user 60 Dec 31 1969 .
< 2012-01-21 01:26:17.203 drwxr-xr-x 3 user user 60 Dec 31 1969 ..
< 2012-01-21 01:26:17.203 drwx------ 2 user user 60 Dec 31 1969 .ssh
< 2012-01-21 01:26:17.222 WinSCP: this is end-of-file:0
. 2012-01-21 01:26:17.222 Startup conversation with host finished.
. 2012-01-21 01:26:19.214 Closing connection.
. 2012-01-21 01:26:19.214 Sending special code: 12
. 2012-01-21 01:26:19.214 Sent EOF message