System Administration 182 Getting Started Guide For example, to allow all hosts in the madison.com domain (whose network address is 192.168.100.0), you would add the following line to /etc/hosts.allow: portmap: 192.168.100.0/255.255.255.0 See the hosts_access(5) and rpc.portmap(8) man pages for complete access con- trol details. To export a filesystem via NFS, so that other systems can mount it, include the directory where the filesystem is mounted on your system in the /etc/exports file. For example, to allow hosts matching *.xmission.com to mount /mnt/source_cd and /mnt/cdrom as read-only filesystems, first add these lines to the /etc/exports file: /mnt/source_cd *.xmission.com(ro) /mnt/cdrom *.xmission.com(ro) Then kill and restart the rpc.nfsd and rpc.mountd daemons so that they will load the new configuration. See the exports(5), rpc.nfsd(8) and rpc.mountd(8) man pages for complete details. For additional details on NFS services, see the manual pages for exports, nfsd, hosts_access (5), mountd and rpc.portmap, as well as the NFS titles listed in the bibliography. Running DOS Programs in OpenLinux OpenLinux includes a DOS emulator and a copy of the DR-DOS operating sys- tem. This capability is installed and available by default if you used the standard OpenLinux installation. To use DOS within OpenLinux, enter this command in character mode or in a graphical terminal emulator window: $ dos