Both reslisa and lisa open a so called raw socket to send and receive ICMP echo requests (pings). To do this, they need root privileges.

lisa offers a service on TCP port 7741, it should be installed by root and started when the system comes up, it depends on your distribution how to do this.
On Slackware linux systems simply enter the following lines into /etc/rc.d/rc.local

if [ -x /usr/local/bin/lisa ]; then
 echo "Starting LISa daemon..."
Of course you have to use the correct path to the lisa daemon on your system, e.g. /opt/kde2/bin/lisa .

If you have Suse Linux 7.3, install the package kdenetwork-lisa. If this is done, edit the template file /etc/lisarc and enter the appropriate values. Then lisa is started automatically everytime you boot your system.

If you are running Suse Linux 7.1, look here for rclisa.tar.gz.
If you have another version of Suse Linux, put the example given above into /etc/init.d/boot.local.

reslisa is intended to be started per user, it doesn't offer anything to the network. It needs to be installed setuid root.

If you use the rlan-ioslave from KDE2, reslisa can be started automatically by the reslisa ioslave (rlan:/).

lisa reads the file lisarc (/etc/lisarc), reslisa reads the file reslisarc (/etc/reslisarc or ~/.reslisarc). If you want to be able to configure both from the KDE Control Center, you have to start them using the command line switch -K or --kde2. For more information where they look for configuration files look here.