端口做为服务器的大门安全很重要，当服务器运行很多服务时并向外提供服务，为防止有人恶意侦测服务器用途，可使用portsentry来迷惑对方

portsentry可设定侦听指定的TCP/UDP端口，当遇到扫描时会回应端口开放，并记录扫描者信息可做相应处理：防火墙阻止、路由定向、执行自定义脚本

实验环境

centos-5.8

实验软件

gcc gcc-c++

portsentry-1.2.tar.gz

软件安装

yum install -y gcc gcc-c++

tar zxvf portsentry-1.2.tar.gz

cd portsentry_beta/

vim portsentry.c

1584   printf ("Copyright 1997-2003 Craig H. Rowland <craigrowland at users dot sourceforget dot net>\n");         次行编译的时候不能折行

make linux

make install

vim /usr/local/psionic/portsentry/portsentry.conf

#TCP_PORTS="1,7,9,11,15,70,79,80,109,110,111,119,138,139,143,512,513,514,515,540,635,1080,1524,2000,2001,4000,4    001,5742,6000,6001,6667,12345,12346,20034,27665,30303,32771,32772,32773,32774,31337,40421,40425,49724,54320"

#UDP_PORTS="1,7,9,66,67,68,69,111,137,138,161,162,474,513,517,518,635,640,641,666,700,2049,31335,27444,34555,32，770,32771,32772,32773,32774,31337,54321"

这两行定义端口策略

83 IGNORE_FILE="/usr/local/psionic/portsentry/portsentry.ignore"

这行定义拒绝ip

87 BLOCKED_FILE="/usr/local/psionic/portsentry/portsentry.blocked"

这行定义拒绝ip记录

132 BLOCK_UDP="1"

133 BLOCK_TCP="1

对扫描IP的操作，0为无动作，1防火墙阻止，2执行脚本

211 KILL_ROUTE="/sbin/ipfw add 1 deny all from $TARGET$:255.255.255.255 to any"

Iptables阻止

/usr/local/psionic/portsentry/portsentry -tcp TCP基本端口绑定，以配置文件端口为准

/usr/local/psionic/portsentry/portsentry -udp  UDP基本端口绑定，以配置文件端口为准

/usr/local/psionic/portsentry/portsentry -stcp TCP私密检测，只记录不回应端口开放

/usr/local/psionic/portsentry/portsentry -sudp UDP私密检测，只记录不回应端口开放

/usr/local/psionic/portsentry/portsentry -stcp UDP高级秘密检测，自动选择监听端口

/usr/local/psionic/portsentry/portsentry -audp UDP高级秘密检测，自动选择监听端口

验证

nmap -sS  www.2cto.com
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-06-11 22:35 CST
Interesting ports on typecho.domain.com (192.168.1.2):
Not shown: 1654 closed ports
PORT      STATE SERVICE
1/tcp     open  tcpmux
11/tcp    open  systat
15/tcp    open  netstat
22/tcp    open  ssh
79/tcp    open  finger
80/tcp    open  http
111/tcp   open  rpcbind
119/tcp   open  nntp
143/tcp   open  imap
443/tcp   open  https
540/tcp   open  uucp
635/tcp   open  unknown
1080/tcp  open  socks
1524/tcp  open  ingreslock
2000/tcp  open  callbook
3306/tcp  open  mysql
6667/tcp  open  irc
12345/tcp open  NetBus
12346/tcp open  NetBus
27665/tcp open  Trinoo_Master
31337/tcp open  Elite
32771/tcp open  sometimes-rpc5
32772/tcp open  sometimes-rpc7
32773/tcp open  sometimes-rpc9
32774/tcp open  sometimes-rpc11
54320/tcp open  bo2k

查看防火墙阻止记录
cat /etc/hosts.deny
ALL: 192.168.1.6

到此为止 PortSentry，就搭建完整了