sudo 简单配置
为了安全考虑，使用sudo是非常有必要的。它能限制指定用户在指定主机上运行某些命令。可以记录每个用户使用sudo做了哪些操作。
sudo的配置文件是：/etc/sudoers
这个文件需要用visudo命令来编辑它。
## Sudoers allows particular users to run various commands as
## the root user, without needing the root password.
##
## Examples are provided at the bottom of the file for collections
## of related commands, which can then be delegated out to particular
## users or groups.
##
## This file must be edited with the 'visudo' command.
## Host Aliases
## Groups of machines. You may prefer to use hostnames (perhap using
## wildcards for entire domains) or IP addresses instead.
# Host_Alias FILESERVERS = fs1, fs2
Host_Alias MAILSERVERS = smtp, smtp2
## User Aliases
## These aren't often necessary, as you can use regular groups
## (ie, from files, LDAP, NIS, etc) in this file - just use %groupname
## rather than USERALIAS
User_Alias ADMINS = jsmith, mikem
## Command Aliases
## These are groups of related commands...
## Networking
Cmnd_Alias NETWORKING = /sbin/route, /sbin/ifconfig, /bin/ping, /sbin/dhclient, /usr/bin/net, /sbin/iptab
les, /usr/bin/rfcomm, /usr/bin/wvdial, /sbin/iwconfig, /sbin/mii-tool
## Installation and management of software
Cmnd_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum
## Services
Cmnd_Alias SERVICES = /sbin/service, /sbin/chkconfig
## Updating the locate database
Cmnd_Alias LOCATE = /usr/sbin/updatedb
## Storage
Cmnd_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount
## Delegating permissions
Cmnd_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp
## Processes
Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall
## Drivers
Cmnd_Alias DRIVERS = /sbin/modprobe
# Defaults specification
#
# Disable "ssh hostname sudo ", because it will show the password in clear.
# You have to run "ssh -t hostname sudo ".
#
Defaults requiretty
Defaults env_reset
Defaults env_keep = "COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR \
LS_COLORS MAIL PS1 PS2 QTDIR USERNAME \
LANG LC_ADDRESS LC_CTYPE LC_COLLATE LC_IDENTIFICATION \
LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC \
LC_PAPER LC_TELEPHONE LC_TIME LC_ALL LANGUAGE LINGUAS \
_XKB_CHARSET XAUTHORITY"
## Next comes the main part: which users can run what software on
## which machines (the sudoers file can be shared between multiple
## systems).
## Syntax:
##
## user MACHINE=COMMANDS
##
## The COMMANDS section may have other options added to it.
##
## Allow root to run any commands anywhere
root ALL=(ALL) ALL
kevin ALL=(ALL) ALL
ADMINS MAILSERVERS=(ALL) NETWORKING
## Allows members of the 'sys' group to run networking, software,
## service management apps and more.
# %sys ALL = NETWORKING, SOFTWARE, SERVICES, STORAGE, DELEGATING, PROCESSES, LOCATE, DRIVERS
## Allows people in group wheel to run all commands
# %wheel ALL=(ALL) ALL
## Same thing without a password
# %wheel ALL=(ALL) NOPASSWD: ALL
## Allows members of the users group to mount and unmount the
## cdrom as root
# %users ALL=/sbin/mount /mnt/cdrom, /sbin/umount /mnt/cdrom
## Allows members of the users group to shutdown this system
# %users localhost=/sbin/shutdown -h now
这里的配置文件大多数都是默认的。我主要讲一下我改动的，红色文字部分。
# Host_Alias MAILSERVERS = smtp, smtp2 和# User_Alias ADMINS = jsmith, mikem这两行“#”删除
root ALL=(ALL) ALL这行下面增加两行
kevin ALL=(ALL) ALL #表示kevin这个用户能sudo任何地方运行命令
ADMINS MAILSERVERS=(ALL) NETWORKING #这行表示ADMINS这个别名下的jsmith, mikem两个用户能在smtp, smtp2两台主机上运行/sbin/route, /sbin/ifconfig,
/bin/ping, /sbin/dhclient, /usr/bin/net, /sbin/iptables, /usr/bin/rfcomm, /usr/bin/wvdial, /sbin/iwconfig, /sbin/mii-tool等
