TCP Wrappers is a software package that has less functionality than a full firewall but is generally available for all Unix and Linux operating systems. TCP Wrappers allows you to restrict access to TCP services, but not UDP or ICMP services. In BU Linux you can also use this to restrict access to RPC services, but this feature is not available for all operating systems and is notably missing in Solaris.
Indiana University has provided good information on How To Use TCP Wrappers that is platform independent but also includes additional information for using the software on Solaris.
TCP Wrappers is installed automatically when a system is installed via IS&T’s Jumpstart program and can also be installed via kickstart or yum on BU Linux.
We also have instructions for Configuring TCP Wrappers on Mac OS X.