I am trying to learn a little more about just what daemons I need running for the system to work and what I can do without.
Now, when I installed Debian, I told dselect to not install things like: ftpd, telnetd, fingerd, talkd, and identd. From memory, the installer wanted to put these on by default. Anyway, I told it not to. I also have a firewall (iptables) which blocks all ports on the external interface unless the packets are part of an already established transmission (initiated from my computer). Now, if I go through my /etc/rc2.d directory and look at all the things getting started. There are only the following: S10sysklogd S20cupsys S20inetd S20postfix S99rmnologin S12kerneld S20gpm S20logoutd S89atd S15firewall_deny S20hotplug S20makedev S89cron The firewall_deny is just my firewall script. So the only daemons that can be connected to I think are: cupsys, inetd, and postfix Now, I can read through the manual on securing cups and postfix (I think) But how do I go about inetd? My inetd.conf looks like: ----------------------------------------------------------------------- # <service_name> <sock_type> <proto> <flags> <user> <server_path> <args> # #:INTERNAL: Internal services #echo stream tcp nowait root internal #echo dgram udp wait root internal #chargen stream tcp nowait root internal #chargen dgram udp wait root internal discard stream tcp nowait root internal discard dgram udp wait root internal daytime stream tcp nowait root internal #daytime dgram udp wait root internal time stream tcp nowait root internal #time dgram udp wait root internal #:STANDARD: These are standard services. #:BSD: Shell, login, exec and talk are BSD protocols. #:MAIL: Mail, news and uucp services. #disabled#smtp stream tcp nowait mail /usr/sbin/exim exim -bs #:INFO: Info services #:BOOT: Tftp service is provided primarily for booting. Most sites # run this only on machines acting as "boot servers." #:RPC: RPC based services #:HAM-RADIO: amateur-radio services #:OTHER: Other services ----------------------------------------------------------------------- So, I am not sure just what I need and what I don't. I know my firewall blocks it all - but I still want to understand what all this stuff in inetd is for. I am just a little confused about the inetd.conf file. Normally, a # is used to comment out things. But, when I had exim (instead of postfix) the Mail line looked like: #smtp stream tcp nowait mail /usr/sbin/exim exim -bs But exim would get run through inetd. So it wasn't commented out? Then when I installed postfix, the installer changed the line to what it is now (with "#disabled" in front) Also, what are discard, daytime and time for. Do I need them? If I comment them out will that stop the OS from accessing the hardware clock? Thanks for educating me. Mark.
