CSTCP_TCPMAXRCVBUFRSIZE

Description:

Checks if the configured TCP maximum receive buffer size is sufficient to provide optimal support to the z/OS® Communications Server FTP Server. The tcpipstackname suffix is the job name of the TCP/IP stack to which this check applies. Use CSTCP_TCPMAXRCVBUFRSIZE_* to reference this check for all stacks.

Reason for check:

Optimally, the z/OS Communications Server FTP Server needs a buffer size of 180K for data connections. TCPMAXRCVBUFRSIZE should not be set below 180K if the z/OS Communications Server FTP Server is being used.

z/OS releases the check applies to:

z/OS V1R8 and later.

User override of IBM® values:

The following shows the default keywords for the check, which you can override on either a POLICY statement in the HZSPRMxx parmlib member or on a MODIFY command. This statement may be copied and modified to override the check defaults:

UPDATE
   CHECK(IBMCS,CSTCP_TCPMAXRCVBUFRSIZE_tcpipstackname)
   DATE('date_of_the_change')
   REASON('Your reason for making the update.')
   PARM('MAXRCVBUFRSIZE(180K)') 
   ACTIVE 
   SEVERITY(LOW) 
   INTERVAL(ONETIME)

Debug support:

Verbose support:

Parameters accepted:

Yes - MAXRCVBUFRSIZE is an integer value with optional suffix (K) indicating the maximum value an application can set as its receive buffer size (in bytes) using SETSOCKOPT(). Value must be in the range 256 to 512K. Default: MAXRCVBUFRSIZE(180K)

Reference:

For more information on TCPMAXRCVBUFRSIZE, see TCPCONFIG in z/OS Communications Server: IP Configuration Reference.

Messages:

This check issues the following exception messages:

EZBH004E

See z/OS Communications Server: IP Messages Volume 2 (EZB, EZD).

SECLABEL recommended for multilevel security users:

SYSLOW - see z/OS Planning for Multilevel Security and the Common Criteria for information on using SECLABELs.