Intermittent 451 Error on Download

This forum is not monitored by the SmartFTP staff. If you have a license please contact technical support by email.
exflor
Posts: 10
Joined: Tue Jun 02, 2009 4:28 pm

Intermittent 451 Error on Download

Post by exflor » Tue Jun 02, 2009 4:49 pm

We are using DownloadFile method to retrieve a file from an FTP server running on an IBM mainframe. Every now and then the download fails with a "451 Transfer aborted: send error." message.

The mainframe folks looking at the server log says that there appears to be two sessions (attempts) to download the file when the download fails. The first one appears to have completed successfully and a second one that fails.

Any ideas on what might be causing the intermittent failures and why the server log shows two sessions?

mb
Posts: 12030
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Intermittent 451 Error on Download

Post by mb » Tue Jun 02, 2009 6:01 pm

Please post the log. Set the LogFile property to get it.

exflor
Posts: 10
Joined: Tue Jun 02, 2009 4:28 pm

Re: Intermittent 451 Error on Download

Post by exflor » Tue Jun 02, 2009 10:31 pm

The following is a log of a successful download. NOTE: (For security reasons the server names,
IP addresses, username, folder and filenames have been replaced.)

********************************************************************************

[20090602 23:20:18] SmartFTP FTP Library v1.5.9.20
[20090602 23:20:18] Resolving host name "FTPSERVER"
[20090602 23:20:18] Connecting to 192.168.1.1 Port: 21
[20090602 23:20:18] Connected to FTPSERVER.
[20090602 23:20:19] 220-FTPD1 IBM FTP CS V1R9 at FTP.SERVER.DOM, 16:20:34 on 2009-06-02.
[20090602 23:20:19] 220 Connection will close if idle for more than 10 minutes.
[20090602 23:20:19] AUTH TLS
[20090602 23:20:19] 234 Security environment established - ready for negotiation
[20090602 23:20:19] Connected. Exchanging encryption keys...
[20090602 23:20:19] Session Cipher: 168 bit 3DES
[20090602 23:20:19] TLS encrypted session established.
[20090602 23:20:19] PBSZ 0
[20090602 23:20:19] 200 Protection buffer size accepted
[20090602 23:20:19] USER FTPUSER
[20090602 23:20:19] 331 Send password please.
[20090602 23:20:19] PASS (hidden)
[20090602 23:20:19] 230 FTPUSER is logged on. Working directory is "FTPUSER.".
[20090602 23:20:19] SYST
[20090602 23:20:19] 215 MVS is the operating system of this server. FTP Server is running on z/OS.
[20090602 23:20:19] Detected Server Type: MVS
[20090602 23:20:19] FEAT
[20090602 23:20:19] 211- Extensions supported
[20090602 23:20:19] SIZE
[20090602 23:20:19] AUTH TLS
[20090602 23:20:19] PBSZ
[20090602 23:20:19] PROT
[20090602 23:20:19] 211 End
[20090602 23:20:19] TYPE I
[20090602 23:20:19] 200 Representation type is Image
[20090602 23:20:19] REST 0
[20090602 23:20:19] 504 Restart not allowed with active security mechanism
[20090602 23:20:19] PWD
[20090602 23:20:19] 257 "'FTPUSER.'" is working directory.
[20090602 23:20:19] CWD 'XXX.YY1234'
[20090602 23:20:19] 250 "XXX.YY1234." is the working directory name prefix.
[20090602 23:20:19] PWD
[20090602 23:20:19] 257 "'XXX.YY1234.'" is working directory.
[20090602 23:20:19] TYPE A
[20090602 23:20:19] 200 Representation type is Ascii NonPrint
[20090602 23:20:19] PROT P
[20090602 23:20:19] 200 Data connection protection set to private
[20090602 23:20:19] PORT 172,19,19,24,13,88
[20090602 23:20:19] 200 Port request OK.
[20090602 23:20:19] RETR TGP1234.XCR
[20090602 23:20:19] Connected. Exchanging encryption keys...
[20090602 23:20:19] 125 Sending data set XXX.YY1234.TGP1234.XCR FIXrecfm 200
[20090602 23:20:19] Session Cipher: 168 bit 3DES
[20090602 23:20:19] TLS encrypted session established.
[20090602 23:20:57] 105270651 bytes transferred. (2.70 MB/s) (00:00:37)
[20090602 23:20:57] 250 Transfer completed successfully.
[20090602 23:20:57] QUIT
[20090602 23:20:57] 221 Quit command received. Goodbye.
[20090602 23:20:57] Client closed the connection.

********************************************************************************



The following are samples of 2 failed download attempts for the same file.

********************************************************************************

[20090602 23:19:14] SmartFTP FTP Library v1.5.9.20
[20090602 23:19:14] Resolving host name "FTPSERVER"
[20090602 23:19:14] Connecting to 192.168.1.1 Port: 21
[20090602 23:19:14] Connected to FTPSERVER.
[20090602 23:19:14] 220-FTPD1 IBM FTP CS V1R9 at FTP.SERVER.DOM, 16:19:29 on 2009-06-02.
[20090602 23:19:14] 220 Connection will close if idle for more than 10 minutes.
[20090602 23:19:14] AUTH TLS
[20090602 23:19:15] 234 Security environment established - ready for negotiation
[20090602 23:19:15] Connected. Exchanging encryption keys...
[20090602 23:19:15] Session Cipher: 168 bit 3DES
[20090602 23:19:15] TLS encrypted session established.
[20090602 23:19:15] PBSZ 0
[20090602 23:19:15] 200 Protection buffer size accepted
[20090602 23:19:15] USER FTPUSER
[20090602 23:19:15] 331 Send password please.
[20090602 23:19:15] PASS (hidden)
[20090602 23:19:15] 230 FTPUSER is logged on. Working directory is "FTPUSER.".
[20090602 23:19:15] SYST
[20090602 23:19:15] 215 MVS is the operating system of this server. FTP Server is running on z/OS.
[20090602 23:19:15] Detected Server Type: MVS
[20090602 23:19:15] FEAT
[20090602 23:19:15] 211- Extensions supported
[20090602 23:19:15] SIZE
[20090602 23:19:15] AUTH TLS
[20090602 23:19:15] PBSZ
[20090602 23:19:15] PROT
[20090602 23:19:15] 211 End
[20090602 23:19:15] TYPE I
[20090602 23:19:15] 200 Representation type is Image
[20090602 23:19:15] REST 0
[20090602 23:19:15] 504 Restart not allowed with active security mechanism
[20090602 23:19:15] PWD
[20090602 23:19:15] 257 "'FTPUSER.'" is working directory.
[20090602 23:19:15] CWD 'XXX.YY1234'
[20090602 23:19:15] 250 "XXX.YY1234." is the working directory name prefix.
[20090602 23:19:15] PWD
[20090602 23:19:15] 257 "'XXX.YY1234.'" is working directory.
[20090602 23:19:15] TYPE A
[20090602 23:19:15] 200 Representation type is Ascii NonPrint
[20090602 23:19:15] PROT P
[20090602 23:19:15] 200 Data connection protection set to private
[20090602 23:19:15] PORT 172,19,19,24,13,67
[20090602 23:19:15] 200 Port request OK.
[20090602 23:19:15] RETR TGP1234.XCR
[20090602 23:19:15] Connected. Exchanging encryption keys...
[20090602 23:19:15] 125 Sending data set XXX.YY1234.TGP1234.XCR FIXrecfm 200
[20090602 23:19:15] Session Cipher: 168 bit 3DES
[20090602 23:19:15] TLS encrypted session established.
[20090602 23:19:51] Transfer Timeout (30s). Closing data connection.
[20090602 23:19:51] 29460842 bytes transferred. (796 KB/s) (00:00:36)
[20090602 23:19:51] 451 Transfer aborted: send error.
[20090602 23:19:51] QUIT
[20090602 23:19:51] 221 Quit command received. Goodbye.
[20090602 23:19:51] Client closed the connection.



[20090602 22:53:27] SmartFTP FTP Library v1.5.9.20
[20090602 22:53:27] Resolving host name "FTPSERVER"
[20090602 22:53:27] Connecting to 192.168.1.1 Port: 21
[20090602 22:53:27] Connected to FTPSERVER.
[20090602 22:53:28] 220-FTPD1 IBM FTP CS V1R9 at FTP.SERVER.DOM, 15:53:43 on 2009-06-02.
[20090602 22:53:28] 220 Connection will close if idle for more than 10 minutes.
[20090602 22:53:28] AUTH TLS
[20090602 22:53:28] 234 Security environment established - ready for negotiation
[20090602 22:53:28] Connected. Exchanging encryption keys...
[20090602 22:53:28] Session Cipher: 168 bit 3DES
[20090602 22:53:28] TLS encrypted session established.
[20090602 22:53:28] PBSZ 0
[20090602 22:53:28] 200 Protection buffer size accepted
[20090602 22:53:28] USER FTPUSER
[20090602 22:53:28] 331 Send password please.
[20090602 22:53:28] PASS (hidden)
[20090602 22:53:28] 230 FTPUSER is logged on. Working directory is "FTPUSER.".
[20090602 22:53:28] SYST
[20090602 22:53:28] 215 MVS is the operating system of this server. FTP Server is running on z/OS.
[20090602 22:53:28] Detected Server Type: MVS
[20090602 22:53:28] FEAT
[20090602 22:53:28] 211- Extensions supported
[20090602 22:53:28] SIZE
[20090602 22:53:28] AUTH TLS
[20090602 22:53:28] PBSZ
[20090602 22:53:28] PROT
[20090602 22:53:28] 211 End
[20090602 22:53:28] TYPE I
[20090602 22:53:28] 200 Representation type is Image
[20090602 22:53:28] REST 0
[20090602 22:53:28] 504 Restart not allowed with active security mechanism
[20090602 22:53:28] PWD
[20090602 22:53:28] 257 "'FTPUSER.'" is working directory.
[20090602 22:53:29] CWD 'XXX.YY1234'
[20090602 22:53:29] 250 "XXX.YY1234." is the working directory name prefix.
[20090602 22:53:29] PWD
[20090602 22:53:29] 257 "'XXX.YY1234.'" is working directory.
[20090602 22:53:29] TYPE A
[20090602 22:53:29] 200 Representation type is Ascii NonPrint
[20090602 22:53:29] PROT P
[20090602 22:53:29] 200 Data connection protection set to private
[20090602 22:53:29] PORT 172,19,19,24,8,70
[20090602 22:53:29] 200 Port request OK.
[20090602 22:53:29] RETR TGP1234.XCR
[20090602 22:53:29] Connected. Exchanging encryption keys...
[20090602 22:53:29] 125 Sending data set XXX.YY1234.TGP1234.XCR FIXrecfm 200
[20090602 22:53:29] Session Cipher: 168 bit 3DES
[20090602 22:53:29] TLS encrypted session established.
[20090602 22:54:39] Transfer Timeout (30s). Closing data connection.
[20090602 22:54:39] 76431187 bytes transferred. (1.03 MB/s) (00:01:10)
[20090602 22:54:39] 451 Transfer aborted: send error.
[20090602 22:54:40] QUIT
[20090602 22:54:40] 221 Quit command received. Goodbye.
[20090602 22:54:40] Client closed the connection.

mb
Posts: 12030
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Intermittent 451 Error on Download

Post by mb » Tue Jun 02, 2009 10:40 pm

The server stop sending data for more than 30 seconds and therefore you get the timeout. Maybe you can find the reason in the server logs.

Regards,
Mat

exflor
Posts: 10
Joined: Tue Jun 02, 2009 4:28 pm

Re: Intermittent 451 Error on Download

Post by exflor » Thu Jun 04, 2009 10:21 pm

I tried turning encryption off and it appears I can download the same file successfully consistently. When I turn on encryption I get the intermittent 451 error for the same file. Any ideas?

mb
Posts: 12030
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Intermittent 451 Error on Download

Post by mb » Fri Jun 05, 2009 3:30 am

Did you run a test with another FTP client?

mb
Posts: 12030
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Intermittent 451 Error on Download

Post by mb » Fri Jun 05, 2009 5:13 am

Please also test it with the latest version of the FTP Library: https://www.smartftp.com/download
The one you are using is almost 2 years old.

Regards,
Mat

exflor
Posts: 10
Joined: Tue Jun 02, 2009 4:28 pm

Re: Intermittent 451 Error on Download

Post by exflor » Fri Jun 05, 2009 3:16 pm

Would our license for the older version work with the latest version?

mb
Posts: 12030
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Intermittent 451 Error on Download

Post by mb » Fri Jun 05, 2009 4:02 pm

Unfortunately no. The maintenance renewal also includes technical support.

Regards,
Mat

exflor
Posts: 10
Joined: Tue Jun 02, 2009 4:28 pm

Re: Intermittent 451 Error on Download

Post by exflor » Sun Jun 07, 2009 11:59 pm

I installed the latest version of the SmartFTP FTP Library, but the problem still persists. We still get intermittent download errors for the same file, with encryption (FTP SSL/TLS Explicit protocol) turned on See sample session logs below. If I turn OFF encryption (plain FTP), I can download the file consistently with no errors.

I also installed WS FTP Pro and configured it to use FTP SSL/TLS Explicit, and I am able to download the same file consistently with no errors.

Are there any other configuration parameters that I should be using specifically when connecting to an FTP server on a mainframe using FTP SSL/TLS Explicit? Any ideas will be greatly appreciated.

Thanks.


The following is a log of a successful download.

********************************************************************************

[20090608 00:33:18] SmartFTP FTP Library v1.5.17.47
[20090608 00:33:18] Resolving host name "FTPSERVER"
[20090608 00:33:18] Connecting to 192.168.1.1 Port: 21
[20090608 00:33:18] Connected to FTPSERVER.
[20090608 00:33:18] 220-FTPD1 IBM FTP CS V1R9 at FTP.SERVER.DOM, 17:33:31 on 2009-06-07.
[20090608 00:33:18] 220 Connection will close if idle for more than 10 minutes.
[20090608 00:33:18] AUTH TLS
[20090608 00:33:18] 234 Security environment established - ready for negotiation
[20090608 00:33:19] Connected. Exchanging encryption keys...
[20090608 00:33:19] Session Cipher: 168 bit 3DES
[20090608 00:33:19] TLS encrypted session established.
[20090608 00:33:19] Command channel protection set to Private.
[20090608 00:33:19] PBSZ 0
[20090608 00:33:19] 200 Protection buffer size accepted
[20090608 00:33:19] USER FTPUSER
[20090608 00:33:19] 331 Send password please.
[20090608 00:33:19] PASS (hidden)
[20090608 00:33:19] 230 FTPUSER is logged on. Working directory is "FTPUSER.".
[20090608 00:33:19] SYST
[20090608 00:33:19] 215 MVS is the operating system of this server. FTP Server is running on z/OS.
[20090608 00:33:19] Detected Server Type: MVS
[20090608 00:33:19] RTT: 2.613 ms
[20090608 00:33:19] FEAT
[20090608 00:33:19] 211- Extensions supported
[20090608 00:33:19] SIZE
[20090608 00:33:19] AUTH TLS
[20090608 00:33:19] PBSZ
[20090608 00:33:19] PROT
[20090608 00:33:19] 211 End
[20090608 00:33:19] TYPE I
[20090608 00:33:19] 200 Representation type is Image
[20090608 00:33:19] REST 0
[20090608 00:33:19] 504 Restart not allowed with active security mechanism
[20090608 00:33:19] PWD
[20090608 00:33:19] 257 "'FTPUSER.'" is working directory.
[20090608 00:33:19] CWD 'XXX.YY1234'
[20090608 00:33:19] 250 "XXX.YY1234." is the working directory name prefix.
[20090608 00:33:19] PWD
[20090608 00:33:19] 257 "'XXX.YY1234.'" is working directory.
[20090608 00:33:19] TYPE A
[20090608 00:33:19] 200 Representation type is Ascii NonPrint
[20090608 00:33:19] PROT P
[20090608 00:33:19] 200 Data connection protection set to private
[20090608 00:33:19] PORT 172,19,19,24,6,38
[20090608 00:33:19] 200 Port request OK.
[20090608 00:33:19] RETR TGP1234.XCR
[20090608 00:33:19] Connected. Exchanging encryption keys...
[20090608 00:33:19] 125 Sending data set XXX.YY1234.TGP1234.XCR FIXrecfm 200
[20090608 00:33:19] Session Cipher: 168 bit 3DES
[20090608 00:33:19] TLS encrypted session established.
[20090608 00:33:19] Socket receive buffer set to 32768 bytes.
[20090608 00:33:19] Socket receive buffer set to 65536 bytes.
[20090608 00:33:21] Socket receive buffer set to 131072 bytes.
[20090608 00:34:01] 105270651 bytes transferred. (2.40 MB/s) (00:00:41)
[20090608 00:34:01] 250 Transfer completed successfully.
[20090608 00:34:01] QUIT
[20090608 00:34:01] 221 Quit command received. Goodbye.
[20090608 00:34:01] Client closed the connection.



********************************************************************************



The following is a log of a failed download.

********************************************************************************

[20090608 00:34:16] SmartFTP FTP Library v1.5.17.47
[20090608 00:34:16] Resolving host name "FTPSERVER"
[20090608 00:34:16] Connecting to 192.168.1.1 Port: 21
[20090608 00:34:16] Connected to FTPSERVER.
[20090608 00:34:16] 220-FTPD1 IBM FTP CS V1R9 at FTP.SERVER.DOM, 17:34:28 on 2009-06-07.
[20090608 00:34:16] 220 Connection will close if idle for more than 10 minutes.
[20090608 00:34:16] AUTH TLS
[20090608 00:34:16] 234 Security environment established - ready for negotiation
[20090608 00:34:16] Connected. Exchanging encryption keys...
[20090608 00:34:16] Session Cipher: 168 bit 3DES
[20090608 00:34:16] TLS encrypted session established.
[20090608 00:34:16] Command channel protection set to Private.
[20090608 00:34:16] PBSZ 0
[20090608 00:34:16] 200 Protection buffer size accepted
[20090608 00:34:16] USER FTPUSER
[20090608 00:34:16] 331 Send password please.
[20090608 00:34:16] PASS (hidden)
[20090608 00:34:16] 230 FTPUSER is logged on. Working directory is "FTPUSER.".
[20090608 00:34:16] SYST
[20090608 00:34:16] 215 MVS is the operating system of this server. FTP Server is running on z/OS.
[20090608 00:34:16] Detected Server Type: MVS
[20090608 00:34:16] RTT: 2.703 ms
[20090608 00:34:16] FEAT
[20090608 00:34:16] 211- Extensions supported
[20090608 00:34:16] SIZE
[20090608 00:34:16] AUTH TLS
[20090608 00:34:16] PBSZ
[20090608 00:34:16] PROT
[20090608 00:34:16] 211 End
[20090608 00:34:16] TYPE I
[20090608 00:34:16] 200 Representation type is Image
[20090608 00:34:16] REST 0
[20090608 00:34:16] 504 Restart not allowed with active security mechanism
[20090608 00:34:16] PWD
[20090608 00:34:16] 257 "'FTPUSER.'" is working directory.
[20090608 00:34:16] CWD 'XXX.YY1234'
[20090608 00:34:16] 250 "XXX.YY1234." is the working directory name prefix.
[20090608 00:34:16] PWD
[20090608 00:34:16] 257 "'XXX.YY1234.'" is working directory.
[20090608 00:34:16] TYPE A
[20090608 00:34:16] 200 Representation type is Ascii NonPrint
[20090608 00:34:16] PROT P
[20090608 00:34:16] 200 Data connection protection set to private
[20090608 00:34:16] PORT 172,19,19,24,6,44
[20090608 00:34:16] 200 Port request OK.
[20090608 00:34:16] RETR TGP1234.XCR
[20090608 00:34:16] Connected. Exchanging encryption keys...
[20090608 00:34:16] 125 Sending data set XXX.YY1234.TGP1234.XCR FIXrecfm 200
[20090608 00:34:16] Session Cipher: 168 bit 3DES
[20090608 00:34:16] TLS encrypted session established.
[20090608 00:34:16] Socket receive buffer set to 32768 bytes.
[20090608 00:34:16] Socket receive buffer set to 65536 bytes.
[20090608 00:34:58] Transfer Timeout (30s). Closing data connection.
[20090608 00:34:58] 27312207 bytes transferred. (637 KB/s) (00:00:41)
[20090608 00:34:58] 451 Transfer aborted: send error.
[20090608 00:34:58] QUIT
[20090608 00:34:58] 221 Quit command received. Goodbye.
[20090608 00:34:58] Client closed the connection.

Post Reply