Check /etc/hostconfig. You might want to make sure everything is the way you want it, like the machine's name etc.:

"sudo open -e /etc/hostconfig" (or "sudo emacs /etc/hostconfig)

(Always remember that the "sudo" command asks for your own password, not a root password.)

This file is usually configured by the system control panels, but the system control panels do not let you configure everything.

Specifically, you might want to change the machine's hostname. Assuming you want to name your machine "charlie", replace

HOSTNAME=-AUTOMATIC-

with

HOSTNAME=charlie

SSHSERVER, WEBSERVER, and APPLETALK_HOSTNAME are modified by the System Preferences Sharing panel. Do it there.

Also check the xinetd folder (/etc/xinetd.d) and consider whether you want Telnet and RLogin to run:

/etc/xinetd.d/login

service login
{
        disable         = no
        socket_type     = stream
        wait            = no
        user            = root
        server          = /usr/libexec/rlogind
        groups          = yes
        flags           = REUSE
}

/etc/xinetd.d/shell

service shell
{
        disable         = no
        socket_type     = stream
        wait            = no
        user            = root
        server          = /usr/libexec/rshd
        groups          = yes
        flags           = REUSE
}

/etc/xinetd.d/telnet

service telnet
{
        disable         = no
        socket_type     = stream
        wait            = no
        user            = root
        server          = /usr/libexec/telnetd
        groups          = yes
        flags           = REUSE
}

But do remember that all three of them are potential security risks (if somebody with evil intentions happens to be able to access your network).

/etc/xinetd.d/ftp

(is configured by System Preferences)

Upgrade to MacOS X 10.2.

See /private/etc/mail/README.

Follow its instructions. Remember that you have to be root (or use sudo) for the nicl instructions to work. Also, add the line

define(`confDONT_BLAME_SENDMAIL', `GroupWritableDirPathSafe')

to yourdomain.mc.

Modify /System/Library/StartupItems/Sendmail/Sendmail and replace

/usr/sbin/sendmail -bd -q1h
/usr/sbin/sendmail -C /etc/mail/submit.cf -q1h

with

/usr/sbin/sendmail -OdontBlameSendmail=GroupWritableDirPathSafe -bd -q1s
/usr/sbin/sendmail -OdontBlameSendmail=GroupWritableDirPathSafe -C /etc/mail/submit.cf -q1s

Start Sendmail with

sudo -b /System/Library/StartupItems/Sendmail/Sendmail start

Also make sure /var/mail has 1777 permissions: "sudo chmod 1777 /var/mail".

You can make it start automatically when you start the system by modifying /etc/hostconfig. Change -NO- to -YES- in the mailserver line. Unless you want to run a mail server you might not need that. If you are afraid of security risks, leave it with -NO-.