IIRC, the SWAT package is sepparate from Samba in Redhat. In Slackware, they are one package, and the file to edit in Slackware is /etc/inetd.conf. In Slackware 8.1, it's all there and you just uncomment the right line. In Slackware 8.0, you had to add it to /etc/services and add it to /etc/inetd.conf as well.
