按端口號可分為3大類：
（1）公認端口（Well Known
Ports）：從0到1023，它們緊密綁定（binding）于一些服務。通常這些端口的通訊明確表明了某種服務的協議。例如：80端口實際上總是HTTP通訊。
（2）注冊端口（Registered
Ports）：從1024到49151。它們松散地綁定于一些服務。也就是說有許多服務綁定于這些端口，這些端口同樣用于許多其它目的。例如：許多系統處理動態端口從1024左右開始。
（3）動態和/或私有端口（Dynamic and/or Private
Ports）：從49152到65535。理論上，不應為服務分配這些端口。實際上，機器通常從1024起分配動態端口。但也有例外：SUN的RPC端口從32768開始。
0
通常用于分析操作系統。這一方法能夠工作是因為在一些系統中“0”是無效端口，當你試圖使用一種通常的閉合端口連接它時將產生不同的結果。一種典型的掃描：使用IP地址為0.0.0.0，設置ACK位并在以太網層廣播。
1 tcpmux TCP Port Service Multiplexer 傳輸控制協議端口服務多路開關選擇器
2 compressnet Management Utility compressnet 管理實用程序
3 compressnet Compression Process 壓縮進程
5 rje Remote Job Entry 遠程作業登錄
7 echo Echo 回顯
9 discard Discard 丟棄
11 systat Active Users 在線用戶
13 daytime Daytime 時間
17 qotd Quote of the Day 每日引用
18 msp Message Send Protocol 消息發送協議
19 chargen Character Generator 字符發生器
20 ftp-data File Transfer[Default Data] 文件傳輸協議(默認數據口)
21 ftp File Transfer[Control] 文件傳輸協議(控制)
22 ssh SSH Remote Login Protocol SSH遠程登錄協議
23 telnet Telnet 終端仿真協議
24 any private mail system 預留給個人用郵件系統
25 smtp Simple Mail Transfer 簡單郵件發送協議
27 nsw-fe NSW User System FE NSW 用戶系統現場工程師
29 msg-icp MSG ICP MSG ICP
31 msg-auth MSG Authentication MSG驗證
33 dsp Display Support Protocol 顯示支持協議
35 any private printer server 預留給個人打印機服務
37 time Time 時間
38 rap Route Access Protocol 路由訪問協議
39 rlp Resource Location Protocol 資源定位協議
41 graphics Graphics 圖形
42 nameserver WINS Host Name Server WINS 主機名服務
43 nicname Who Is “綽號” who is服務
44 mpm-flags MPM FLAGS Protocol MPM(消息處理模塊)標志協議
45 mpm Message Processing Module [recv] 消息處理模塊
46 mpm-snd MPM [default send] 消息處理模塊(默認發送口)
47 ni-ftp NI FTP NI FTP
48 auditd Digital Audit Daemon 數碼音頻后臺服務
49 tacacs Login Host Protocol (TACACS) TACACS登錄主機協議
50 re-mail-ck Remote Mail Checking Protocol 遠程郵件檢查協議[未結束]
51 la-maint IMP Logical Address Maintenance IMP(接口信息處理機)邏輯地址維護
52 xns-time XNS Time Protocol 施樂網絡服務系統時間協議
53 domain Domain Name Server 域名服務器
54 xns-ch XNS Clearinghouse 施樂網絡服務系統票據交換
55 isi-gl ISI Graphics Language ISI圖形語言
56 xns-auth XNS Authentication 施樂網絡服務系統驗證
57 any private terminal access 預留個人用終端訪問
58 xns-mail XNS Mail 施樂網絡服務系統郵件
59 any private file service 預留個人文件服務
60 Unassigned 未定義
61 ni-mail NI MAIL NI郵件
62 acas ACA Services 異步通訊適配器服務
63 whois+ whois+ WHOIS+
64 covia Communications Integrator (CI) 通訊接口
65 tacacs-ds TACACS-Database Service TACACS數據庫服務
66 sql*net Oracle SQL*NET Oracle SQL*NET
67 bootps Bootstrap Protocol Server 引導程序協議服務端
68 bootpc Bootstrap Protocol Client 引導程序協議客戶端
69 tftp Trivial File Transfer 小型文件傳輸協議
70 gopher Gopher 信息檢索協議
71 netrjs-1 Remote Job Service 遠程作業服務
72 netrjs-2 Remote Job Service 遠程作業服務
73 netrjs-3 Remote Job Service 遠程作業服務
74 netrjs-4 Remote Job Service 遠程作業服務
75 any private dial out service 預留給個人撥出服務
76 deos Distributed External Object Store 分布式外部對象存儲
77 any private RJE service 預留給個人遠程作業輸入服務
78 vettcp vettcp 修正TCP
79 finger Finger 查詢遠程主機在線用戶等信息
80 http World Wide Web HTTP 全球信息網超文本傳輸協議
81 hosts2-ns HOSTS2 Name Server HOST2名稱服務
82 xfer XFER Utility 傳輸實用程序
83 mit-ml-dev MIT ML Device 模塊化智能終端ML設備
84 ctf Common Trace Facility 公用追蹤設備
85 mit-ml-dev MIT ML Device 模塊化智能終端ML設備
86 mfcobol Micro Focus Cobol Micro Focus Cobol編程語言
87 any private terminal link 預留給個人終端連接
88 kerberos Kerberos Kerberros安全認證系統
89 su-mit-tg SU/MIT Telnet Gateway SU/MIT終端仿真網關
90 dnsix DNSIX Securit Attribute Token Map DNSIX
安全屬性標記圖
91 mit-dov MIT Dover Spooler MIT Dover假脫機
92 npp Network Printing Protocol 網絡打印協議
93 dcp Device Control Protocol 設備控制協議
94 objcall Tivoli Object Dispatcher Tivoli對象調度
95 supdup SUPDUP
96 dixie DIXIE Protocol Specification DIXIE協議規范
97 swift-rvf（Swift Remote Virtural File Protocol）快速遠程虛擬文件協議
98 tacnews TAC News TAC新聞協議
99 metagram Metagram Relay
100 newacct [unauthorized use]
101=NIC Host Name Server
102=ISO-TSAP
103=Genesis Point-to-Point Trans Net
104=ACR-NEMA Digital Imag. & Comm. 300
105=Mailbox Name Nameserver
106=3COM-TSMUX3com-tsmux
107=Remote Telnet Service
108=SNA Gateway Access Server
109=Post Office Protocol – Version 2
110=Post Office Protocol – Version 3
111=SUN RPC
112=McIDAS Data Transmission Protocol
113=Authentication Service
114=Audio News Multicast
115=Simple File Transfer Protocol
116=ANSA REX Notify
117=UUCP Path Service
118=SQL Servicessqlserv
119=Network News Transfer Protocol
120=CFDPTKTcfdptkt
121=Encore Expedited Remote Pro.Call
122=SMAKYNETsmakynet
123=Network Time Protocol
124=ANSA REX Trader
125=Locus PC-Interface Net Map Ser
126=Unisys Unitary Login
127=Locus PC-Interface Conn Server
128=GSS X License Verification
129=Password Generator Protocol
130=cisco FNATIVE
131=cisco TNATIVE
132=cisco SYSMAINT
133=Statistics Service
134=INGRES-NET Service
135=Location Service
136=PROFILE Naming System
137=NETBIOS Name Service
138=NETBIOS Datagram Service
139=NETBIOS Session Service
140=EMFIS Data Service
141=EMFIS Control Service
142=Britton-Lee IDM
143=Interim Mail Access Protocol v2
144=NewSnews
145=UAAC Protocoluaac
146=ISO-IP0iso-tp0
147=ISO-IPiso-ip
148=CRONUS-SUPPORT
149=AED 512 Emulation Service
150=SQL-NETsql-net
151=HEMShems
152=Background File Transfer Program
153=SGMPsgmp
154=NETSCnetsc-prod
155=NETSCnetsc-dev
156=SQL Service
157=KNET/VM Command/Message Protocol
158=PCMail Serverpcmail-srv
159=NSS-Routingnss-routing
160=SGMP-TRAPSsgmp-traps
161=SNMP
162=SNMP TRAP
163=CMIP/TCP Manager
164=CMIP/TCP Agent
165=Xeroxxns-courier
166=Sirius Systems
167=NAMPnamp
168=RSVDrsvd
169=Send
170=Network PostScript
170=Network PostScript
171=Network Innovations Multiplex
172=Network Innovations CL/1
173=Xyplexxyplex-mux
174=MAILQ
175=VMNET
176=GENRAD-MUXgenrad-mux
177=X Display Manager Control Protocol
178=NextStep Window Server
179=Border Gateway Protocol
180=Intergraphris
181=Unifyunify
182=Unisys Audit SITP
183=OCBinderocbinder
184=OCServerocserver
185=Remote-KIS
186=KIS Protocolkis
187=Application Communication Interface
188=Plus Five s MUMPS
189=Queued File Transport
189=Queued File Transport
190=Gateway Access Control Protocol
190=Gateway Access Control Protocol
191=Prospero Directory Service
191=Prospero Directory Service
192=OSU Network Monitoring System
193=srmp, Spider Remote Monitoring Protocol
194=irc, Internet Relay Chat Protocl
195=DNSIX Network Level Module Audit
196=DNSIX Session Mgt Module Audit Redir
197=Directory Location Service
198=Directory Location Service Monitor
199=SMUX
200=IBM System Resource Controller
201=at-rtmp AppleTalk Routing Maintenance
202=at-nbp AppleTalk Name Binding
203=at-3 AppleTalk Unused
204=AppleTalk Echo
205=AppleTalk Unused
206=AppleTalk Zone Information
207=AppleTalk Unused
208=AppleTalk Unused
209=Trivial Authenticated Mail Protocol
210=ANSI Z39.50z39.50
211=Texas Instruments 914C/G Terminal
212=ATEXSSTRanet
213=IPX
214=VM PWSCSvmpwscs
215=Insignia Solutions
216=Access Technology License Server
217=dBASE Unix
218=Netix Message Posting Protocol
219=Unisys ARPsuarps
220=Interactive Mail Access Protocol v3
221=Berkeley rlogind with SPX auth
222=Berkeley rshd with SPX auth
223=Certificate Distribution Center
224=Reserved (224-241)
241=Reserved (224-241)
242=Unassigned#
243=Survey Measurement
244=Unassigned#
245=LINKlink
246=Display Systems Protocol
247-255 Reserved
256-343 Unassigned
