On RedHat 8.x and above, there is a Gnome UI that effects initialization changes, under "Server Settings"/"Services". This can be used to install and remove services, much like the way chkconfig works.
/etc/rc.d/rc*.d:
Links in these directories are numbered. At system initialization, when the system reaches the run level that matches the number in the directory name (e.g. /etc/rc.d/rc2.d is run level 2), the directory is scanned and each of the links found in it is run in ascending order to start up the system services.
The links are soft links and are added with the "ln" command. For example, to add a link for the packetfilter at run level 3, do:
ln -s ../init.d/packetfilter /etc/rc.d/rc3.d/S09packetfilter
/etc/rc.d/rc0.d:
After K90network, add these links:
K91packetfilter --> ../init.d/packetfilter
K92ipchains --> ../init.d/ipchains
/etc/rc.d/rc1.d:
After K90network, add these links:
K91packetfilter --> ../init.d/packetfilter
K92ipchains --> ../init.d/ipchains
/etc/rc.d/rc2.d:
Before S10network, add this link:
S08ipchains --> ../init.d/ipchains
/etc/rc.d/rc3.d:
After S05kudzu and before S10network, add the following links:
S08ipchains --> ../init.d/ipchains
S09antispoofing --> ../init.d/antispoofing
S09packetfilter --> ../init.d/packetfilter
After S10network, add this link:
S11dialdaemon --> ../init.d/dialdaemon
/etc/rc.d/rc4.d:
Before S10network, add this link:
S08ipchains --> ../init.d/ipchains
/etc/rc.d/rc5.d:
Before S10network, add this link:
S08ipchains --> ../init.d/ipchains
/etc/rc.d/rc6.d:
After K90network, add these links:
K91packetfilter --> ../init.d/packetfilter
K92ipchains --> ../init.d/ipchains
chkconfig
For those startup scripts that are properly defined, you can use chkconfig to add their symbolic links to the appropriate places in the rc.d directory structure. See "man chkconfig" for more info. In general, do the following:
chkconfig --add startscript
chkconfig startscript on