TCP/IP applications
refer to networked computers via their fully qualified domain names
(FQDN) and their IP addresses. Because IP addresses can change easily,
SAS applications that contain hardcoded IP addresses are prone to
maintenance problems. To avoid such problems, use of an FQDN is preferred
over an IP address. The name-resolution system that is part of the
TCP/IP protocol is responsible for locating the IP address that is
associated with the FQDN.
SAS 9.2 introduced support
for the Internet Protocol, IPv6, which is the successor to Internet
Protocol, IPv4. Rather than replacing IPv4 with IPv6, SAS now supports
both protocols. There will be a lengthy transition period during which
the two protocols will coexist. A primary reason for the new protocol
is that the limited supply of 32-bit IPv4 address spaces was being
depleted. IPv6 uses a 128-bit address scheme, which provides more
IP addresses than does IPv4.
Here are examples of
an FQDN, an IPv6 address, and an IPv4 address:
d6292.us.company.com
db8::01
10.23.2.3
For details, see Internet Protocol Version 6 (IPv6) in SAS Language Reference: Concepts.