在LINUX系統上建立FTP加密傳輸

作者：llzqq
聯系：llzqq@126.com
來自：www.chinaunix.net

在眾多的FTP服務器中PROFTPD由于它的配置靈活，安裝簡便。近年來一直受到人們的喜愛。通常情況下FTP包括認證過程，傳輸是明文傳輸的，在傳輸一些敏感數據時總是不能讓人放心。今天我在網上找了一些零散的資料結合自己的實作寫了個帖子貢獻給大家。

下載最新的軟件版本：

# wget ftp://ftp.proftpd.org/distrib/source/proftpd-1.3.0rc3.tar.gz

首先創建ROFTPD運行的用戶和組：

# groupadd nogroup
# useradd –g nogroup –d /dev/null –s /sbin/nologin nobody

首先創建上傳下載的用戶和組：

# groupadd ftp
# useradd –g ftp –d /home/down –s /sbin/nologin down
# useradd –g ftp –d /home/upload –s /sbin/nologin upload
用戶密碼設置略

編譯安裝PROFRPD:

# tar –zxvf proftpd-1.3.0rc3.tar.gz
# cd proftpd-1.3.0rc3
# ./configure
--prefix=/usr/local/proftpd
--sysconfdir=/etc
--enable-autoshadow
--localstatedir=/var/run
--enable-ctrls
--with-modules=mod_tls

# make
# make install

配置PROFTPD服務器：

# vi /etc/proftpd.conf
================+================+=================
# This is a basic ProFTPD configuration file (rename it to
# 'proftpd.conf' for actual use. It establishes a single server
# and a single anonymous login. It assumes that you have a user/group
# nobody and ftp for normal operation and anon.
ServerName llzqq
ServerType standalone
DefaultServer on
AllowRetrieveRestart on
AllowStoreRestart on
ServerType standalone
ServerIdent on
SystemLog /var/log/proftpd.log
UseReverseDNS off
IdentLookups off
RequireValidShell off
# Port 21 is the standard FTP port.
Port 21
# Umask 022 is a good standard umask to prevent new dirs and files
# from being group and world writable.
Umask 022
MaxInstances 100
# Set the user and group under which the server will run.
User nobody
Group nogroup
# To cause every FTP user to be jailed (chrooted) into their home
# directory, uncomment this line.
DefaultRoot ~
# Normally, we want files to be overwriteable.
Directory />
AllowOverwrite on
/Directory>
# We want 'welcome.msg' displayed at login, and '.message' displayed
# in each newly chdired directory.
DisplayLogin .welcome
DisplayFirstChdir .message
# Limit User of being enbled login ftp server
Limit LOGIN>
AllowGroup ftp
DenyAll
/Limit>
#########################ssl/tls############################
# MOD_TLS SETTING
IfModule mod_tls.c>
TLSEngine on
TLSLog /var/log/proftpd-tls.log
TLSProtocol SSLv23
# Are clients required to use FTP over TLS when talking to this server?
TLSRequired ctrl
# Server's certificate
TLSRSACertificateFile /etc/proftpd.crt
TLSRSACertificateKeyFile /etc/proftpd.key
# Authenticate clients that want to use FTP over TLS
TLSVerifyClient off
#########################ssl/tls############################
Directory /home/down>
Limit WRITE>
DenyGroup ftp
/Limit>
TransferRate RETR 150 group ftp
/Directory>
Directory /home/upload>
Limit RMD RNFR DELE RETR>
DenyGroup ftp
/Limit>
TransferRate STOR 150 group ftp
/Directory>
MaxClientsPerHost 200
PassivePorts 55000 56000
================+================+=================

創建PROFTPD的日志文件：

# touch /var/log/proftpd.log
# touch /var/log/proftpd-tls.log
# chown nobody:nogroup /var/log/proftpd.log /var/log/proftpd-tls.log

創建SSL傳輸的證書和密匙：

# cp /usr/share/ssl/openssl.cnf ./
# openssl req -new -x509 -nodes -config openssl.cnf -out proftpd.crt –keyout proftpd.key
這里安裝提示需要輸入證書信息略

把證書和密匙復制到指定目錄：
# cp proftpd.crt proftpd.key /etc/

最后創建PROFTPD啟動教本：

# vi /etc/init.d/proftpd
================+================+=================
#!/bin/sh
# Startup script for ProFTPD
# chkconfig: 345 85 15
# description: ProFTPD is an enhanced FTP server
# processname: proftpd
# config: /etc/proftpd.conf
# Source function library.
. /etc/rc.d/init.d/functions

if [ -f /etc/sysconfig/proftpd ]; then
. /etc/sysconfig/proftpd
fi
PATH=$PATH:/usr/local/proftpd/sbin
# See how we were called.
case $1 in
start)
echo -n Starting proftpd:
daemon proftpd $OPTIONS
echo
touch /var/lock/subsys/proftpd
;;
stop)
echo -n Shutting down proftpd:
killproc proftpd
echo
rm -f /var/lock/subsys/proftpd
;;
status)
status proftpd
;;
restart)
$0 stop
$0 start
;;
reread)
echo -n Re-reading proftpd config:
killproc proftpd -HUP
echo
;;
suspend)
hash ftpshut >/dev/null 2>1
if [ $? = 0 ]; then
if [ $# -gt 1 ]; then
shift
echo -n Suspending with '$*'
ftpshut $*
else
echo -n Suspending NOW
ftpshut now Maintanance in progress
fi
else
echo -n No way to suspend
fi
echo
;;
resume)
if [ -f /etc/shutmsg ]; then
echo -n Allowing sessions again
rm -f /etc/shutmsg
else
echo -n Was not suspended
fi
echo
;;
*)
echo -n Usage: $0 {start|stop|restart|status|reread|resume
hash ftpshut
if [ $? = 1 ]; then
echo '}'
else
echo '|suspend}'
echo 'suspend accepts additional arguments which are passed to ftpshut(8)'
fi
exit 1
esac

if [ $# -gt 1 ]; then
shift
$0 $*
fi
exit 0
================+================+=================

# chomd 755 /etc/init.d/proftpd
# chkconfig –-add proftpd
# chkconfig proftpd on

到這里ftp服務器端安裝設置完畢，登陸服務器的客戶端我用了完全免費的FileZilla（前兩天網上看到說FileZilla支持SSL不錯）。FileZilla的設置也比較簡單。本服務器支持兩種客戶端加密連接方式：

1. FTP over ssl (顯示加密)方式連接。
2. FTP over tls (顯示加密) 方式連接