A fix is available
APAR status
Closed as new function.
Error description
Certain FTP Clients have hard coded control connection timeouts of 60 seconds. When trying to take advantage of DSWAITTIME, these clients do not work as it is a race between whether their 60 second timeout timer pops, and the 125- reply is sent from the FTP Server. In order to enhance interoperability, a new parameter will be introduced to allow control over how often the FTP Server sends the 125- reply indicating that we are still waiting for exclusive access to a dataset.
Local fix
Use a client where the control connection timeout can be adjusted.
Problem summary
**************************************************************** * USERS AFFECTED: All users of the IBM Communications Server * * for z/OS Version 1 Release(s) 11 and 12 * * IP: FTP * **************************************************************** * PROBLEM DESCRIPTION: An FTP client which can not adjust its * * timeout value to be greater than a * * minute for the control connection can * * not take advantage of the z/OS FTP * * server's DSWAITTIME function. * **************************************************************** * RECOMMENDATION: * **************************************************************** The z/OS FTP server's DSWAITTIME function provides a retry capability in minutes if the z/OS data set is unavailable (for example, being edited). The interval of checking file in z/OS FTP server is in 1 minute increments. The z/OS FTP server sends a 125 reply to FTP client every minute to let the FTP client know that the connection is active. However, a minute is too long for some FTP clients, so the control connection is closed. +-------------------------------------------------------------+ + Please check our Communications Server for OS/390 homepages + + for common networking tips and fixes. The URL for these + + homepages can be found in Informational APAR II11334. + +-------------------------------------------------------------+
Problem conclusion
Temporary fix
Comments
Code has been modified to support a new server FTP.DATA statement, DSWAITTIMEREPLY with possible values from 15 to 60. The following documentation updates will be made. * FUNCTION AFFECTED: Communications Server TCP/IP (PM36004) * * FTP * * DESCRIPTION : Documentation updates * * TIMING : None * IBM Communications Server: IP Configuration Reference SC318776 Change DSWAITTIME (FTP client and server) statement From Guidelines: . The FTP server ignores the DSWAITTIME configuration option for RENAME FROM (RNFR), RENAME TO (RNTO), and DELETE (DELE) commands. . If the DSWAITTIME configuration option is not 0, also specify DATAKEEPALIVE configuration option. To Guidelines: . The FTP server ignores the DSWAITTIME configuration option for RENAME FROM (RNFR), RENAME TO (RNTO), and DELETE (DELE) commands. . If the DSWAITTIME configuration option is not 0, also specify DATAKEEPALIVE configuration option. . If you experience control connection time-outs while the server is waiting for access to an MVS data set, try configuring a nonzero value for FTPKEEPALIVE at the client or the server. If keepalive packets do not prevent FTP control connection time-outs, configure a smaller DSWAITTIMEREPLY value. From Related topics . DATAKEEPALIVE (FTP client and server) statement . FTPKEEPALIVE (FTP client and server) statement . REPLYSECURITYLEVEL (FTP server) statement To Related topics . DSWAITTIMEREPLY (FTP server) statement . DATAKEEPALIVE (FTP client and server) statement . FTPKEEPALIVE (FTP client and server) statement . REPLYSECURITYLEVEL (FTP server) statement Add the following under FTP.DATA data set statements DSWAITTIMEREPLY (FTP server) statement Use the DSWAITTIMEREPLY statement to specify how often to send a line of the reply 125-Data set access will be retried in 1 minute intervals -- <number> attempts remaining to the client while the FTP server is waiting for access to an MVS data set. Results: . The server always issues the reply 125--FTP Server unable to obtain <usage> use of <data set> which is held by <asid< <jobname> <accessmode> on <qname> at one minute intervals while waiting for access to a data set for the amount of time specified by the DSWAITTIME configuration option. By default, the server sends this reply to the client at one minute intervals also: 125-Data set access will be retried at 1 minute intervals -- <number> attempts remaining Code a DSWAITTIMEREPLY value smaller than 60 to cause the server to send this reply more frequently. . The DSWAITTIMEREPLY value is applied only when you have configured a DSWAITTIME value greater than zero. Tip: Coding a DSWAITTIMEREPLY value smaller than 60 can prevent an FTP client control connection from timing out while the server is waiting for a data set. Syntax -DSWAITTIMEREPLY 60------- >>__|___________________________|________________________<< | | -DSWAITTIMEREPLY seconds-- Parameters seconds The number of seconds between reply lines 125-data set access will be retried in 1 minute intervals - <number> attempts remaining that the server sends to the client while it is waiting for access to an MVS data set. The valid range is 15 to 60. The default is 60 seconds. Examples In this example, DSWAITTIMEREPLY 30 The reply 125-Data Set access will be retried in 1 minute intervals -- <number> attempts remaining is issued every thirty (30) seconds. If DSWAITTIME is set to 3, the actual output should be 125-FTP Server unable to obtain EXCLUSIVE use of USER.TEST.DATA which is held by: 0035 USER2 EXCL on SYSDSN 125-Data set access will be retried in 1 minute intervals - 3 attempts remaining 125-Data set access will be retried in 1 minute intervals - 3 attempts remaining 125-FTP Server unable to obtain EXCLUSIVE use of USER.TEST.DATA which is held by: 0035 USER2 EXCL on SYSDSN 125-Data set access will be retried in 1 minute intervals - 2 attempts remaining 125-Data set access will be retried in 1 minute intervals - 2 attempts remaining 125-FTP Server unable to obtain EXCLUSIVE use of USER.TEST.DATA which is held by: 0035 USER2 EXCL on SYSDSN 125-Data set access will be retried in 1 minute intervals - 1 attempts remaining 125-Data set access will be retried in 1 minute intervals - 1 attempts remaining 125-FTP Server unable to obtain EXCLUSIVE use of USER.TEST.DATA which is held by: 0035 USER2 EXCL on SYSDSN 125 Data set USER2.TEST.DATA is not available Related topic DSWAITTIME (FTP client and server) statement FTPKEEPALIVE (FTP client and server) statement ================================================================ IBM Communications Server: IP User's Guide and Commands SC318780 Add the following to the SITE Subcommands Add the following 2 lines into the format chart: |___DSWAITTIMEREPLY_=_ ___60_____| | |_seconds_ | And add the following descriptions: DSWAITTIMEREPLY specify the interval for sending a line of the reply 125-Data set access will be retried in 1 minute intervals -- <number> attempts remaining to the client while the FTP server is waiting for access to an data set. seconds The number of seconds between reply lines 125-data set access will be retried in 1 minute intervals - <number> attempts remaining that the server sends to the client while it is waiting for access to an MVS data set. The valid range is 15 to 60. The default is 60 seconds. ================================================================ IBM Communications Server: Quick Reference SX750124 Chapter 2. TSO commands SITE subcommand Send site specific information to a host: Add DSWAITTIMEREPLY alphabetically to the syntax diagram for the site subcommand. |___DSWAITTIMEREPLY_=_ ___60_____| | |_seconds_ | ================================================================ IBM Communications Server: IP and SNA Codes SC318791 Change 125- Data set access will be retried in 1 minute intervals - number attempts remaining From This reply is part of a sequence of 125- replies. This 125- reply is issued each time the FTP server attempts to obtain the data set. This reply indicates how many more attempts to access the MVS data set remain. The FTP server pauses after each of these replies for approximately 1 minute until the next attempt is made to access the MVS data set. To This reply is part of a sequence of 125- replies. This reply is issued every DSWAITTIMEREPLY seconds while the server is waiting to obtain the data set. This reply indicates how many more attempts to access the MVS data set remain. The FTP server pauses after each of these replies for approximately 1 minute until the next attempt is made to access the MVS data set.
APAR Information
APAR number
PM36004
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
1B0
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2011-03-31
Closed date
2011-05-26
Last modified date
2011-07-05
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK68204 UK68205 PM41777
Modules/Macros
EZAFTPAS EZAFTPCY EZAFTPDM EZAFTPED EZAFTPEH EZAFTPEP EZAFTPGL EZAFTPGM EZAFTPMK EZAFTPMV EZAFTPM9 EZAFTPRM EZAFTPRR EZAFTPRS EZAFTPRT EZAFTPRX EZAFTPSD EZAFTPSM EZAFTPSR
| SC31877618 | SC31878009 | SX75012410 | SC31877615 | SC31878009 |
| SX75012409 | SC31879110 | SC31879109 |
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
05 July 2011