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
来源：oschina
链接：https://my.oschina.net/u/4380585/blog/4301538