every time I shut down my computer the computer reports that it can't kill cannaserver because it is run by another machine.
Are you on a LAN and have other hosts that use japanese translation? If not, please post a more exact error description, if yes, and you don't want them to use your Canna, can you install Canna on those hosts?
1. Most processes the system needs are run as "daemons", that is, in the background, and often as a different user than "root". The user account these processes run as can not be used to login with, making the daemon safer to use and still have some needed privileges like being able to read, open or write to files. The numerical ID for these users is usually between 10 and 100 or 500. User ID's over 500, usually are human users.
2. Canna is the japanese (kana to kanji/romaji) translations server. I don't use Canna, and I don't know if it's run tru Xinetd. For this I'm going to assert it's running in standalone mode and your distro is Red Hat. If run tru Xinetd, look in /etc/xinetd.d. If not Red Hat, find out how your distro handles package management. To find out which Canna version is installed, as root, type "rpm -qa | grep -ie canna". Now to find out the contents of that package, type "rpm -qlv Canna-<version>". Where version is what you got from the first query. To cross-check which user Canna is running as, type "find / -type f -name Canna.conf | xargs -ix egrep 'x' -e "^canna(Owner|Group)". AFAIK this should be an unprivileged user, with a numerical ID over at least 50, presumably user "canna": "grep /etc/passwd -ie "^canna" should tell. "netstat -anp" or "lsof -i" should give you the unique process ID (PID) a process is run as which you can manipulate (as in send a signal like KILL), the binary name and in case of lsof also the user it's being run as. Now if you have the process PID, then run "strings /proc/<insert pid here>/status" and all the info you found out like process name, user ID etc etc should correlate with earlier findings.
The routine described above can be run on any service you have questions about to find out the details (also see "whatis", "slocate", "apropos" and "man" Just feed the name of the app as argument). You prolly wonder why this can't be automated. It can be, but it's good to know the manual routines. Google around for Chkrootkit(.org), Tiger (Savannah.nongnu.org), Aide (or Samhain or tripwire), Lsat and check out the
LQ FAQ: Security references. I recommend you at least install and use the first three apps I mentioned.
Now you know what's running on your box, determine which services you need to run, and want to allow people to have access to. If you conclude you don't need some services, read their documentation and search LQ for it just to make sure you don't need 'em, then deinstall. If you need the services yourself, but don't want to have remote hosts accessing them, there are basically 4 basic mechanisms to restrict usage:
1. Daemon configuration. Most server daemons allow you to place restrictions on who can access them.
2. TCP Wrappers (aka libwrap). The /etc/hosts.{deny,allow} files allow you to control who can access a service from any address or range. Xinetd also uses libwrap.
3. PAM. Used by services that need a user to login.
4. The firewall. It's called "Netfilter" but in kernel v2.4 you know it as "iptables", in 2.2 as "ipchains". It allows you to define rules that allow/deny access to a service from any address or range.
