FTP2 fails with T01F2029I VLT ERROR: VLT RC=05 B:Can't connect to Local Host, RC = 5

Document ID : KB000050162
Last Modified Date : 14/02/2018
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Description:

FTPs fail with the VLT error. They may run when restarted later.

Solution:

FTP2 uses VTAM in order to run.

Each FTP2 client instance requires 2 VTAM LUs; one for an internal local FTP control connection and one for the remote FTP control connection.

The LUs defined must be part of the VTAM major node defined for TCPaccess and are accessed through a module called ACCPOOL.

ACCPOOL is located in the tcpaccess.LINK library located either in the LINKLIST or STEPLIBed in the batchjob.

By default we supply 30 LUs (enough for 15 concurrent FTP2 jobs) with names of ACCVLT01 - ACCVLT30.

The ACCPOOL module can be updated using a usermod called UMODPOOL. Source for this usermod can be found in the tcpaccess.SAMP library and instructions for use are in the Customization Guide Chapter 9, under the section Modifying VTAMLST Application Definitions.

In all instances, the T01F2029I VLT ERROR: VLT RC=05 error occurs when no LUs are available for the current FTP job.

Possible causes:

  1. The LUs in the ACCPOOL module do not match your VTAM definitions

  2. -This can occur if your VTAM definitions do not match what was distributed. In that case, the UMODPOOL was implemented at some point and the ACCPOOL should contain different LU names than what is distributed.

    If maintenance is applied to SMP/E and the complete LINK library was copied - or maintenance was applied on a different system and the libraries copied to the system having the problem, it is very likely that the ACCPOOL module was overwritten with one that does not match the current environment, so the LUs are incorrect. In this case, you must locate a correct version of the ACCPOOL module and re-implement it or re-run UMODPOOL.

  3. 1. LUs in the ACCPOOL are already in use.

    The LUs defined in VTAM are used by ACCPOOL and the APPLUPxx PARM member.

    The APPLUPxx member is pointed to in the APPCFGxx and supplies LUs for Telnet.
    Both ACCPOOL and APPLUPxx pull their LUs from the same VTAM major node.
    In cases where there is an LU overlap ( LUs defined in the ACCPOOL are also defined in the APPLUPxx), whoever accesses the LU first has it.
    In some instances that can mean that no LUs at all are available to FTP if long-term Telnet users have accessed all of them.
    Check to see whether an overlap exists. Depending on your environment, you may simply remove some LUs from the APPLUP,
    run UMODPOOL to change (or increase) the LU's in the ACCPOOL module, or a combination of both along with a modification to your VTAM definitions.

  4. 1. The number of LUs in the ACCPOOL is insufficient.

    Whether the default ACCPOOL module is in use or whether it has been customized, changes to the mainframe environment or increases in FTP traffic may produce more concurrent FTPs than can be handled by the current number of LUs defined in the ACCPOOL module. If you have 50 LUs defined (25 concurrent FTPs) then maybe that number needs to be increased to 100. Again, this may require adjustments to either APPLUPxx and / or your VTAM definitions.

If none of the above appears to apply, please obtain a TCPEEP and VLT trace and contact support.

TCPEEP parameters:

 TCPEEP TRCSSID(ACTR) +        
 GROUPS((NETIF,'TYPE(IP),+ 
                  HOST(138.42.32.165),+
                  MDATA(128),+
                  PROTOCOL(TCP),+
                  PORT(20,21)')) +
 FORMAT(DATA(128),TCP) +
 NOHEADER

Where TRCSSID matches the SSID of your RUNTRACE address space
HOST is the IP address of the remote where the FTP is failing.

The VLT trace is activated by adding VLT to your EXEC statement and a SYSVLT DD in the JCL.

Example:

 //STEP1           EXEC PGM=FTP2,PARM='/ FIOS VLT'      
             : 
             :
             :
 //SYSVLT          DD SYSOUT=*,BLKSIZE=133