Enabling IPv6 support

z/OS®Communications Server can be run as an IPv4-only stack or as a dual-mode stack (IPv4 and IPv6). The BPXPRMxx parmlib member determines which mode is used. The following configurations are possible:

INET IPv4 only
INET IPv4/IPv6 dual-mode stack
CINET IPv4 only
CINET IPv4/IPv6 dual-mode stack

Restriction: After a stack has been started, you must stop and restart the stack to change the mode of the stack.

You can configure AF_INET alone or both AF_INET and AF_INET6. Although coding AF_INET6 alone is not prohibited, TCP/IP does not start because the master socket is AF_INET and the call to open it fails.

INET IPv4-only BPXPRMxx sample definition

IPv4-only stack support is defined by using one NETWORK statement (for AF_INET) in the BPXPRMxx parmlib member. For example:

FILESYSTYPE Type(INET) Entrypoint(EZBPFINI)    
NETWORK DOMAINNAME(AF_INET)          
        DOMAINNUMBER(2)     
        MAXSOCKETS(2000) 
        TYPE(INET)

INET IPv4/IPv6 dual-mode stack BPXPRMxx sample definition

Dual-mode stack support is defined by using two NETWORK statements (one for AF_INET and one for AF_INET6) in the BPXPRMxx parmlib member. For example:

FILESYSTYPE Type(INET) Entrypoint(EZBPFINI)    
NETWORK DOMAINNAME(AF_INET)          
        DOMAINNUMBER(2)     
        MAXSOCKETS(2000) 
        TYPE(INET)     
NETWORK DOMAINNAME(AF_INET6)          
        DOMAINNUMBER(19)     
        MAXSOCKETS(3000) 
        TYPE(INET)

Separate MAXSOCKETS values are supported. The IPv6 default is the IPv4 specified value.

CINET IPv4-only BPXPRMxx sample definition

Multiple TCP/IP stacks in one MVS™ image or LPAR are supported only by using Common INET (CINET). Each TCP/IP stack is defined in the BPXPRMxx parmlib member using a SUBFILESYSTYPE statement. These definitions are identical to what was used before IPv6 support. The following example shows the definitions for three IPv4-only stacks:

FILESYSTYPE TYPE(CINET) ENTRYPOINT (BPXTCINT)    
NETWORK DOMAINNAME(AF_INET)  
        DOMAINNUMBER(2)   
        MAXSOCKETS(2000)   
        TYPE(CINET)        
        INADDRANYPORT(20000)       
        INADDRANYCOUNT(100) 
SUBFILESYSTYPE NAME(TCPCS)  TYPE(CINET) ENTRYPOINT(EZBPFINI) 
SUBFILESYSTYPE NAME(TCPCS2) TYPE(CINET) ENTRYPOINT(EZBPFINI)
SUBFILESYSTYPE NAME(TCPCS3) TYPE(CINET) ENTRYPOINT(EZBPFINI)

CINET IPv4/IPv6 dual-mode stack BPXPRMxx sample definition

Dual-mode (IPv4/IPv6) stack support is defined by using two NETWORK statements in the BPXPRMxx member. Each TCP/IP stack is defined in the BPXPRMxx parmlib member by using a SUBFILESYSTYPE statement. All z/OS Communications Server stacks that are defined under the two NETWORK statements are dual-mode (IPv4/IPv6) stacks. The following example shows the definitions for three dual-mode stacks:

FILESYSTYPE TYPE(CINET) ENTRYPOINT(BPXTCINT)    
NETWORK DOMAINNAME(AF_INET)   
         DOMAINNUMBER(2)     
         MAXSOCKETS(2000)      
         TYPE(CINET)       
         INADDRANYPORT(20000)          
         INADDRANYCOUNT(100) 
NETWORK DOMAINNAME(AF_INET6)  
         DOMAINNUMBER(19)    
         MAXSOCKETS(3000)     
         TYPE(CINET)
SUBFILESYSTYPE NAME(TCPCS)  TYPE(CINET) ENTRYPOINT(EZBPFINI) 
SUBFILESYSTYPE NAME(TCPCS2) TYPE(CINET) ENTRYPOINT(EZBPFINI)
SUBFILESYSTYPE NAME(TCPCS3) TYPE(CINET) ENTRYPOINT(EZBPFINI)