inetd is often also used to start identd. Or identd may run as a
stand-alone service. Basically, identd (note this is identd not inetd)
is used to return information (usually the username) of the user running
the process that has a TCP/IP connection. Some believe that is needed
to track down abuse, spam or to make better authentication; but, by
default, identd is not secure, so its reporting may not be entirely
reliable. Usually identd is considered to be not needed and I have
successfully administrated a variety of webservers without any ident
atd is similar to cron, because it is also used to run scheduled jobs.
Unless you specifically use the “at” capabilities, you don’t need atd —
use cron instead.
gpm (or moused) is a program that allows you to use your mouse to cut
and paste text on your console screen. This may be a handy feature, but
is it really needed on a webserver? How often are you going to be
sitting at the console and needing to use a mouse?
apmd is a daemon for use with an Advanced Power Management (APM) BIOS
Interface-based system. If you’re interested in your
server going into standby or suspend modes or you need to monitor the
battery usage, then use apmd. As you can tell, apmd is for laptops and
or environment-friendly (or “green”) machines; apmd is not needed for an
always running webserver.
lpd is the line printer daemon — basically it is for handling printer
by managing spools (or queues). If you don’t need a constantly, readily
available printer for your webserver, then lpd shouldn’t be running.
If you do need to print out something, simply copy it to another
computer or temporarily turn on lpd (make sure it is configured so
outside computers can’t access it).
Sendmail is a MTA — a mail transfer agent. Some other popular MTAs
include Exim, qmail and postfix. These MTAs can be used as a mail server
to listen for incoming email and/or to relay email to another server.
If your server is not providing email services — or in other words, is
not a mail server, then sendmail doesn’t need to be always running.
If improperly configured, sendmail can be abused; for example, spammers
may be able to relay mail through your system. (Some admins run the MTA
via inetd — so another good reason to disable inetd.)
Do not remove the MTA — your system will still need it to send out
email. (But you should consider configuring it, so it can’t listen to
to the network.)
Also, some admins believe that sendmail needs to be always
running to manage the queue. Unless, you have some huge amount of email
activity, use cron to have sendmail process its queue a few times a day.
(This doesn’t mean that it will only send mail a few times a day.
sendmail will try to send the email when first invoked — it will only
queue it if it had a problem.)
portmap (or rpc.portmap) is a server that converts RPC program numbers
to DARPA protocol port numbers. Huh? Basically, portmap is used to help
with RPC-type services like NFS (Network File System). (rpcbind is
similar to portmap). So, unless you use NFS, you probably don’t need
portmap running. You may have other processes running that provide RPC
or NFS services (such as nfsd, rpc.mountd, rpc.nfsd, rpc.statd and
rpc.lockd). Again if you don’t use them, then they can be disabled.
Of course, there are numerous other programs that may be running.
Some other examples of programs that aren’t needed (and probably should
be stopped) include xfs, fvwm, xinit and X.
If you use remote management tools (like webmin or Comanche), you
may need to keep inetd or other daemons running to be able to use them.
Be sure to also read the tool’s documentation.
Use your manual pages, system documentation and search engines (like
Google’s Usenet Search) to learn more about any other daemons and to
help you make a decision.