PortMap 3
by Wietse Venema
Categories: Access Control, Libraries, Replacement, RPC
This is the 3rd enhanced portmapper release. The code compiles fine with SunOS 4.1.x, Ultrix 4.x and ESIX System V release 4.0, but it will work with many other UNIX flavors. Tested with SunOS 4.1.1; an earlier version was also tested with Ultrix 3.0. SysV.4 uses a different program that the portmapper, however; rpcbind is the name, and it can do much more than the old portmapper. This is a portmapper replacement with access control in the style of the tcp wrapper (log_tcp) package. It provides a simple mechanism to discourage access to the NIS (YP), NFS, and other services registered with the portmapper. In some cases, better or equivalent alternatives are available. The SunOS portmap that is provided with patch id100482-02 should close the same security holes. In addition, it provides NIS daemons with their own access control lists. This is better than just portmapper access control. The "securelib" shared library ( implements access control for all kinds of (RPC) services, not just the portmapper. Reportedly, Irix 4.0.x already has a secured portmapper. However, many vendors still ship portmap implementations that allow anyone to read or modify its tables and that will happily forward any request so that it appears to come from the local system.

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