nmap是Linux下常用的端口扫描工具，它可以检测主机是否在线，是否开启了某个服务端口，使用了何种操作系统等。我经常用它来检测远程的Windows服务器的ip地址，因为不是固定ip地址，该服务器的ip地址会经常变化，但是有个规律，只在一个网段内变化，这样就给ip地址的确定带来了方便。
1. 如果没有安装nmap，就安装
yum install -y nmap
2. 扫描指定网段的远程桌面连接端口
nmap -sT -p3389 218.206.112.0/24
3. 如果觉得输出太多，可以用 grep 命令过滤
nmap -sT -p3389 218.206.112.0/24 | grep -B2 open
下面是操作的消息记录，备查。
[[email protected] opt]# nmap
-bash: nmap: command not found
[[email protected] opt]# yum install -y nmap
Loaded plugins: fastestmirror
Determining fastest mirrors
* base: mirrors.163.com
* extras: ftp.iij.ad.jp
* updates: rsync.atworks.co.jp
base | 1.1 kB 00:00
extras | 1.9 kB 00:00
extras/primary_db | 172 kB 00:00
updates | 1.9 kB 00:00
updates/primary_db | 828 kB 00:03
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package nmap.i386 2:4.11-2 set to be updated
--> Finished Dependency Resolution
Dependencies Resolved
========================================================================================================================================================================
Package Arch Version Repository Size
========================================================================================================================================================================
Installing:
nmap i386 2:4.11-2 base 660 k
Transaction Summary
========================================================================================================================================================================
Install 1 Package(s)
Upgrade 0 Package(s)
Total download size: 660 k
Downloading Packages:
nmap-4.11-2.i386.rpm | 660 kB 00:00
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : nmap 1/1
Installed:
nmap.i386 2:4.11-2
Complete!
[[email protected] opt]# nmap
Nmap 4.11 ( http://www.insecure.org/nmap/ )
Usage: nmap [Scan Type(s)] [Options] {target specification}
TARGET SPECIFICATION:
Can pass hostnames, IP addresses, networks, etc.
Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.0-255.1-254
-iL : Input from list of hosts/networks
-iR : Choose random targets
--exclude <HOST1[,HOST2][,HOST3],...>: Exclude hosts/networks
--excludefile : Exclude list from file
HOST DISCOVERY:
-sL: List Scan - simply list targets to scan
-sP: Ping Scan - go no further than determining if host is online
-P0: Treat all hosts as online -- skip host discovery
-PS/PA/PU [portlist]: TCP SYN/ACK or UDP discovery to given ports
-PE/PP/PM: ICMP echo, timestamp, and netmask request discovery probes
-n/-R: Never do DNS resolution/Always resolve [default: sometimes]
--dns-servers <SERV1[,SERV2],...>: Specify custom DNS servers
--system-dns: Use OS's DNS resolver
SCAN TECHNIQUES:
-sS/sT/sA/sW/sM: TCP SYN/Connect()/ACK/Window/Maimon scans
-sN/sF/sX: TCP Null, FIN, and Xmas scans
--scanflags : Customize TCP scan flags
-sI : Idlescan
-sO: IP protocol scan
-b : FTP bounce scan
PORT SPECIFICATION AND SCAN ORDER:
-p : Only scan specified ports
Ex: -p22; -p1-65535; -p U:53,111,137,T:21-25,80,139,8080
-F: Fast - Scan only the ports listed in the nmap-services file)
-r: Scan ports consecutively - don't randomize
SERVICE/VERSION DETECTION:
-sV: Probe open ports to determine service/version info
--version-intensity : Set from 0 (light) to 9 (try all probes)
--version-light: Limit to most likely probes (intensity 2)
--version-all: Try every single probe (intensity 9)
--version-trace: Show detailed version scan activity (for debugging)
OS DETECTION:
-O: Enable OS detection
--osscan-limit: Limit OS detection to promising targets
--osscan-guess: Guess OS more aggressively
TIMING AND PERFORMANCE:
Options which take
(seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30m).
-T[0-5]: Set timing template (higher is faster)
--min-hostgroup/max-hostgroup : Parallel host scan group sizes
--min-parallelism/max-parallelism
--min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout
probe round trip time.
--max-retries : Caps number of port scan probe retransmissions.
--host-timeout
--scan-delay/--max-scan-delay
FIREWALL/IDS EVASION AND SPOOFING:
-f; --mtu : fragment packets (optionally w/given MTU)
-D <DECOY1,DECOY2[,ME],...>: Cloak a scan with decoys
-S : Spoof source address
-e : Use specified interface
-g/--source-port : Use given port number
--data-length : Append random data to sent packets
--ttl : Set IP time-to-live field
--spoof-mac : Spoof your MAC address
--badsum: Send packets with a bogus TCP/UDP checksum
OUTPUT:
-oN/-oX/-oS/-oG : Output scan in normal, XML, s|
and Grepable format, respectively, to the given filename.
-oA : Output in the three major formats at once
-v: Increase verbosity level (use twice for more effect)
-d[level]: Set or increase debugging level (Up to 9 is meaningful)
--packet-trace: Show all packets sent and received
--iflist: Print host interfaces and routes (for debugging)
--log-errors: Log errors/warnings to the normal-format output file
--append-output: Append to rather than clobber specified output files
--resume : Resume an aborted scan
--stylesheet : XSL stylesheet to transform XML output to HTML
--webxml: Reference stylesheet from Insecure.Org for more portable XML
--no-stylesheet: Prevent associating of XSL stylesheet w/XML output
MISC:
-6: Enable IPv6 scanning
-A: Enables OS detection and Version detection
--datadir : Specify custom Nmap data file location
--send-eth/--send-ip: Send using raw ethernet frames or IP packets
--privileged: Assume that the user is fully privileged
-V: Print version number
-h: Print this help summary page.
EXAMPLES:
nmap -v -A scanme.nmap.org
nmap -v -sP 192.168.0.0/16 10.0.0.0/8
nmap -v -iR 10000 -P0 -p 80
SEE THE MAN PAGE FOR MANY MORE OPTIONS, DESCRIPTIONS, AND EXAMPLES
[[email protected] opt]#
[[email protected] opt]# nmap -sT -p3389 218.206.112.0/24
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-10-26 15:36 CST
Interesting ports on 218.206.112.1:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.11:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.16:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.39:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.40:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.41:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.49:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.51:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.56:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.59:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.65:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.68:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.69:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.71:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.72:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.74:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.77:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.78:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.80:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.81:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.82:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.83:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.87:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.88:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.94:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.95:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.96:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.100:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.102:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.103:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.105:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.107:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.108:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.109:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.110:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.111:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.116:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.117:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.119:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.121:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.123:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.129:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.131:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.132:
PORT STATE SERVICE
3389/tcp open ms-term-serv
Interesting ports on 218.206.112.134:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.136:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.144:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.147:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.150:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.156:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.157:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.160:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.163:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.165:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.179:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.181:
PORT STATE SERVICE
3389/tcp closed ms-term-serv
Interesting ports on 218.206.112.188:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Interesting ports on 218.206.112.190:
PORT STATE SERVICE
3389/tcp filtered ms-term-serv
Nmap finished: 256 IP addresses (58 hosts up) scanned in 22.497 seconds
[[email protected] opt]#
[[email protected] opt]#
[[email protected] opt]#
[[email protected] opt]# nmap -sT -p3389 218.206.112.0/24 | grep -B2 open
Interesting ports on 218.206.112.100:
PORT STATE SERVICE
3389/tcp open ms-term-serv
--
Interesting ports on 218.206.112.132:
PORT STATE SERVICE
3389/tcp open ms-term-serv
[[email protected] opt]#
