列举常用的TCP和UDP端口及其应用程序的功能
TCP/IP协议端口一栏表 _____# GoSH portlist compiled by Julian Assange - proff@suburbuia.net## Please send any additions / clarifications to strobe@suburbia.net#reserved 0/tcp Reserved [JBP]reserved 0/udp Reserved [JBP]tcpmux1/tcp TCP Port Service Multiplexer [MKL]tcpmux1/udp TCP Port Service Multiplexer [MKL]compressnet 2/tcp Management Utility [BV15]compressnet 2/udp Management Utility [BV15]compressnet 3/tcp Compression Process [BV15]compressnet 3/udp Compression Process [BV15]rje5/tcp Remote Job Entry [12,JBP]rje5/udp Remote Job Entry [12,JBP]echo7/tcp Echo [95,JBP]echo7/udp Echo [95,JBP]discard9/tcp Discard [94,JBP]discard9/udp Discard [94,JBP]systat 11/tcp Active Users [89,JBP]systat 11/udp Active Users [89,JBP]daytime 13/tcp Daytime [93,JBP]daytime 13/udp Daytime [93,JBP]netstat 15/tcp Netstatqotd 17/tcp Quote of the Day [100,JBP]qotd 17/udp Quote of the Day [100,JBP]msp 18/tcp Message Send Protocol [RXN]msp 18/udp Message Send Protocol [RXN]chargen 19/tcp ttytst source Character Generatorchargen 19/udp ttytst source Character Generatorftp-data20/tcp File Transfer [Default Data] [96,JBP]ftp-data20/udp File Transfer [Default Data] [96,JBP]ftp 21/tcp File Transfer [Control] [96,JBP]ftp 21/udp File Transfer [Control] [96,JBP]ssh 22/tcp Secure Shell - RSA encrypted rshtelnet 23/tcp Telnet [112,JBP]telnet 23/udp Telnet [112,JBP]priv-mail24/tcp any private mail system [RA11]priv-mail24/udp any private mail system [RA11]smtp 25/tcp Simple Mail Transfer [102,JBP]smtp 25/udp Simple Mail Transfer [102,JBP]nsw-fe 27/tcp NSW User System FE [24,RHT]nsw-fe 27/udp NSW User System FE [24,RHT]msg-icp 29/tcp MSG ICP [85,RHT]msg-icp 29/udp MSG ICP [85,RHT]msg-auth31/tcp MSG Authentication [85,RHT]msg-auth31/udp MSG Authentication [85,RHT]dsp 33/tcp Display Support Protocol [EXC]dsp 33/udp Display Support Protocol [EXC]priv-print35/tcp any private printer server [JBP]priv-print35/udp any private printer server [JBP]time 37/tcp Time [108,JBP]time 37/udp Time [108,JBP]rap 38/tcp Route Access Protocolrap 38/udp Route Access Protocolrlp 39/tcp resource Resource Location Protocolrlp 39/udp resource Resource Location Protocolgraphics41/tcp Graphics [129,JBP]graphics41/udp Graphics [129,JBP]nameserver42/tcp Host Name Server [99,JBP]nameserver42/udp Host Name Server [99,JBP]nicname 43/tcp Who Is [55,ANM2]nicname 43/udp Who Is [55,ANM2]mpm-flags44/tcp MPM FLAGS Protocol [JBP]mpm-flags44/udp MPM FLAGS Protocol [JBP]mpm 45/tcp Message Processing Module [recv] [98,JBP]mpm 45/udp Message Processing Module [recv] [98,JBP]mpm-snd 46/tcp MPM [default send] [98,JBP]mpm-snd 46/udp MPM [default send] [98,JBP]ni-ftp 47/tcp NI FTP [134,SK8]ni-ftp 47/udp NI FTP [134,SK8]auditd 48/tcp Digital Audit Daemonauditd 48/udp Digital Audit Daemonlogin 49/tcp Login Host Protocol [PHD1]login 49/udp Login Host Protocol [PHD1]re-mail-ck50/tcp Remote Mail Checking Protocol [171,SXD1]re-mail-ck50/udp Remote Mail Checking Protocol [171,SXD1]la-maint51/tcp IMP Logical Address Maintenance [76,AGM]la-maint51/udp IMP Logical Address Maintenance [76,AGM]xns-time52/tcp XNS Time Protocol [SXA]xns-time52/udp XNS Time Protocol [SXA]domain 53/tcp Domain Name Server [81,95,PM1]domain 53/udp Domain Name Server [81,95,PM1]xns-ch 54/tcp XNS Clearinghouse [SXA]xns-ch 54/udp XNS Clearinghouse [SXA]isi-gl 55/tcp ISI Graphics Language [7,RB9]isi-gl 55/udp ISI Graphics Language [7,RB9]xns-auth56/tcp XNS Authentication [SXA]xns-auth56/udp XNS Authentication [SXA]mtp 57/tcp deprecatedpriv-term57/tcp any private terminal access [JBP]priv-term57/udp any private terminal access [JBP]xns-mail58/tcp XNS Mail [SXA]xns-mail58/udp XNS Mail [SXA]priv-file59/tcp any private file service [JBP]priv-file59/udp any private file service [JBP]ni-mail 61/tcp NI MAIL [5,SK8]ni-mail 61/udp NI MAIL [5,SK8]acas 62/tcp ACA Services [EXW]acas 62/udp ACA Services [EXW]via-ftp 63/tcp VIA Systems - FTP [DXD]via-ftp 63/udp VIA Systems - FTP [DXD]whois++ 63/tcpwhois++ 63/udpcovia 64/tcp Communications Integrator (CI) [TXD]covia 64/udp Communications Integrator (CI) [TXD]tacacs-ds65/tcp TACACS-Database Service [3,KH43]tacacs-ds65/udp TACACS-Database Service [3,KH43]sql*net 66/tcp Oracle SQL*NET [JFH2]sql*net 66/udp Oracle SQL*NET [JFH2]bootps 67/tcp Bootstrap Protocol Server [36,WJC2]bootps 67/udp Bootstrap Protocol Server [36,WJC2]bootpc 68/tcp Bootstrap Protocol Client [36,WJC2]bootpc 68/udp Bootstrap Protocol Client [36,WJC2]tftp 69/tcp Trivial File Transfer [126,DDC1]tftp 69/udp Trivial File Transfer [126,DDC1]gopher 70/tcp Gopher [MXC1]gopher 70/udp Gopher [MXC1]netrjs-171/tcp Remote Job Service [10,RTB3]netrjs-171/udp Remote Job Service [10,RTB3]netrjs-272/tcp Remote Job Service [10,RTB3]netrjs-272/udp Remote Job Service [10,RTB3]netrjs-373/tcp Remote Job Service [10,RTB3]netrjs-373/udp Remote Job Service [10,RTB3]netrjs-474/tcp Remote Job Service [10,RTB3]netrjs-474/udp Remote Job Service [10,RTB3]priv-dial75/tcp any private dial out service [JBP]priv-dial75/udp any private dial out service [JBP]deos 76/tcp Distributed External Object Storedeos 76/udp Distributed External Object Storenetrjs 77/tcppriv-rje77/tcp any private RJE service [JBP]priv-rje77/udp any private RJE service [JBP]vettcp 78/tcp vettcp [CXL1]vettcp 78/udp vettcp [CXL1]finger 79/tcp Finger [52,KLH]finger 79/udp Finger [52,KLH]http 80/tcp www www-http World Wide Web HTTPhttp 80/udp www www-http World Wide Web HTTPwww 80/tcp World Wide Web HTTP [TXL]www 80/udp World Wide Web HTTP [TXL]hosts2-ns81/tcp HOSTS2 Name Server [EAK1]hosts2-ns81/udp HOSTS2 Name Server [EAK1]xfer 82/tcp XFER Utility [TXS2]xfer 82/udp XFER Utility [TXS2]mit-ml-dev83/tcp MIT ML Device [DXR3]mit-ml-dev83/udp MIT ML Device [DXR3]ctf 84/tcp Common Trace Facility [HXT]ctf 84/udp Common Trace Facility [HXT]mit-ml-dev85/tcp MIT ML Device [DXR3]mit-ml-dev85/udp MIT ML Device [DXR3]mfcobol 86/tcp Micro Focus Cobol [SXE]mfcobol 86/udp Micro Focus Cobol [SXE]priv-term-l87/tcp any private terminal link [JBP]priv-term-l87/udp any private terminal link [JBP]ttylink 87/tcpkerberos88/tcp Kerberos [BCN]kerberos88/udp Kerberos [BCN]su-mit-tg89/tcp SU/MIT Telnet Gateway [MRC]su-mit-tg89/udp SU/MIT Telnet Gateway [MRC]dnsix 90/tcp DNSIX Securit Attribute Token Map [CXW1]dnsix 90/udp DNSIX Securit Attribute Token Map [CXW1]mit-dov 91/tcp MIT Dover Spooler [EBM]mit-dov 91/udp MIT Dover Spooler [EBM]npp 92/tcp Network Printing Protocol [LXM]npp 92/udp Network Printing Protocol [LXM]dcp 93/tcp Device Control Protocol [DT15]dcp 93/udp Device Control Protocol [DT15]objcall 94/tcp Tivoli Object Dispatcher [TXB1]objcall 94/udp Tivoli Object Dispatcher [TXB1]supdup 95/tcp SUPDUP [27,MRC]supdup 95/udp SUPDUP [27,MRC]dixie 96/tcp DIXIE Protocol Specification [TXH1]dixie 96/udp DIXIE Protocol Specification [TXH1]swift-rvf97/tcp Swift Remote Vitural File Protocol [MXR]swift-rvf97/udp Swift Remote Vitural File Protocol [MXR]tacnews 98/tcp TAC News [ANM2]tacnews 98/udp TAC News [ANM2]metagram99/tcp Metagram Relay [GEOF]metagram99/udp Metagram Relay [GEOF]newacct100/tcp [unauthorized use]hostname 101/tcp hostnames NIC Host Name Serverhostname 101/udp hostnames NIC Host Name Serveriso-tsap 102/tcp tsap ISO-TSAP Class 0iso-tsap 102/udp tsap ISO-TSAP Class 0gppitnp103/tcp Genesis Point-to-Point Trans Net [PXM1]gppitnp103/udp Genesis Point-to-Point Trans Net [PXM1]x400103/tcp ISO Mailacr-nema 104/tcp ACR-NEMA Digital Imag. & Comm. 300 [PXM1]acr-nema 104/udp ACR-NEMA Digital Imag. & Comm. 300 [PXM1]x400-snd 104/tcp ISO Mailcsnet-ns 105/tcp Mailbox Name Nameserver [127,MS56]csnet-ns 105/udp Mailbox Name Nameserver [127,MS56]3com-tsmux 106/tcp 3COM-TSMUX [JXS5]3com-tsmux 106/udp 3COM-TSMUX [JXS5]rtelnet107/tcp Remote Telnet Service [101,JBP]rtelnet107/udp Remote Telnet Service [101,JBP]snagas108/tcp SNA Gateway Access Server [KXM]snagas108/udp SNA Gateway Access Server [KXM]pop2109/tcp postoffice Post Office Protocol - Version 2pop2109/udp postoffice Post Office Protocol - Version 2pop3110/tcp Post Office Protocol - Version 3 [122,MTR]pop3110/udp Post Office Protocol - Version 3 [122,MTR]sunrpc111/tcp rpcbind SUN Remote Procedure Callsunrpc111/udp rpcbind SUN Remote Procedure Callmcidas112/tcp McIDAS Data Transmission Protocol [GXD]mcidas112/udp McIDAS Data Transmission Protocol [GXD]auth113/tcp Authentication Service [130,MCSJ]auth113/udp Authentication Service [130,MCSJ]audionews 114/tcp Audio News Multicast [MXF2]audionews 114/udp Audio News Multicast [MXF2]sftp115/tcp Simple File Transfer Protocol [73,MKL1]sftp115/udp Simple File Transfer Protocol [73,MKL1]ansanotify 116/tcp ANSA REX Notify [NXH]ansanotify 116/udp ANSA REX Notify [NXH]uucp-path 117/tcp UUCP Path Service [44,MAE]uucp-path 117/udp UUCP Path Service [44,MAE]sqlserv118/tcp SQL Services [LXB3]sqlserv118/udp SQL Services [LXB3]nntp119/tcp Network News Transfer Protocol [65,PL4]nntp119/udp Network News Transfer Protocol [65,PL4]cfdptkt120/tcp CFDPTKT [JXO3]cfdptkt120/udp CFDPTKT [JXO3]erpc121/tcp Encore Expedited Remote Pro.Call [132,JXO]erpc121/udp Encore Expedited Remote Pro.Call [132,JXO]smakynet 122/tcp SMAKYNET [MXO]smakynet 122/udp SMAKYNET [MXO]ntp123/tcp Network Time Protocol [80,DLM1]ntp123/udp Network Time Protocol [80,DLM1]ansatrader 124/tcp ANSA REX Trader [NXH]ansatrader 124/udp ANSA REX Trader [NXH]locus-map 125/tcp Locus PC-Interface Net Map Ser [137,EP53]locus-map 125/udp Locus PC-Interface Net Map Ser [137,EP53]unitary126/tcp Unisys Unitary Login [FEIL]unitary126/udp Unisys Unitary Login [FEIL]locus-con 127/tcp Locus PC-Interface Conn Server [137,EP53]locus-con 127/udp Locus PC-Interface Conn Server [137,EP53]gss-xlicen 128/tcp GSS X License Verification [JXL]gss-xlicen 128/udp GSS X License Verification [JXL]pwdgen129/tcp Password Generator Protocol [141,FJW]pwdgen129/udp Password Generator Protocol [141,FJW]cisco-fna 130/tcp cisco FNATIVE [WXB]cisco-fna 130/udp cisco FNATIVE [WXB]cisco-tna 131/tcp cisco TNATIVE [WXB]cisco-tna 131/udp cisco TNATIVE [WXB]cisco-sys 132/tcp cisco SYSMAINT [WXB]cisco-sys 132/udp cisco SYSMAINT [WXB]statsrv133/tcp Statistics Service [DLM1]statsrv133/udp Statistics Service [DLM1]ingres-net 134/tcp INGRES-NET Service [MXB]ingres-net 134/udp INGRES-NET Service [MXB]loc-srv135/tcp Location Service [JXP]loc-srv135/udp Location Service [JXP]profile136/tcp PROFILE Naming System [LLP]profile136/udp PROFILE Naming System [LLP]netbios-ns 137/tcp NETBIOS Name Service [JBP]netbios-ns 137/udp NETBIOS Name Service [JBP]netbios-dgm 138/tcp NETBIOS Datagram Service [JBP]netbios-dgm 138/udp NETBIOS Datagram Service [JBP]netbios-ssn 139/tcp NETBIOS Session Service [JBP]netbios-ssn 139/udp NETBIOS Session Service [JBP]emfis-data 140/tcp EMFIS Data Service [GB7]emfis-data 140/udp EMFIS Data Service [GB7]emfis-cntl 141/tcp EMFIS Control Service [GB7]emfis-cntl 141/udp EMFIS Control Service [GB7]bl-idm142/tcp Britton-Lee IDM [SXS1]bl-idm142/udp Britton-Lee IDM [SXS1]imap2143/tcp Interim Mail Access Protocol v2 [MRC]imap2143/udp Interim Mail Access Protocol v2 [MRC]NeWS144/tcp Window SystemNeWS144/udp Window Systemnews144/tcp NewS window system [JAG]news144/udp NewS window system [JAG]uaac145/tcp UAAC Protocol [DAG4]uaac145/udp UAAC Protocol [DAG4]iso-tp0146/tcp ISO-IP0 [86,MTR]iso-tp0146/udp ISO-IP0 [86,MTR]iso-ip147/tcp ISO-IP [MTR]iso-ip147/udp ISO-IP [MTR]cronus148/tcp CRONUS-SUPPORT [135,JXB]cronus148/udp CRONUS-SUPPORT [135,JXB]aed-512149/tcp AED 512 Emulation Service [AXB]aed-512149/udp AED 512 Emulation Service [AXB]sql-net150/tcp SQL-NET [MXP]sql-net150/udp SQL-NET [MXP]hems151/tcp HEMS [87,CXT]hems151/udp HEMS [87,CXT]bftp152/tcp Background File Transfer Program [AD14]bftp152/udp Background File Transfer Program [AD14]sgmp153/tcp SGMP [37,MS9]sgmp153/udp SGMP [37,MS9]netsc-prod 154/tcp NETSC [SH37]netsc-prod 154/udp NETSC [SH37]netsc-dev 155/tcp NETSC [SH37]netsc-dev 155/udp NETSC [SH37]sqlsrv156/tcp SQL Service [CMR]sqlsrv156/udp SQL Service [CMR]knet-cmp 157/tcp KNET/VM Command/Message Protocol[77,GSM11]knet-cmp 157/udp KNET/VM Command/Message Protocol[77,GSM11]pcmail-srv 158/tcp PCMail Server [19,MXL]pcmail-srv 158/udp PCMail Server [19,MXL]nss-routing 159/tcp NSS-Routing [JXR]nss-routing 159/udp NSS-Routing [JXR]sgmp-traps 160/tcp SGMP-TRAPS [37,MS9]sgmp-traps 160/udp SGMP-TRAPS [37,MS9]snmp161/tcp SNMP [15,MTR]snmp161/udp SNMP [15,MTR]snmptrap 162/tcp SNMPTRAP [15,MTR]snmptrap 162/udp SNMPTRAP [15,MTR]cmip-man 163/tcp CMIP/TCP Manager [4,AXB1]cmip-man 163/udp CMIP/TCP Manager [4,AXB1]cmip-agent 164/tcp CMIP/TCP Agentsmip-agent 164/udp CMIP/TCP Agentxns-courier 165/tcp Xerox 144,SXA]xns-courier 165/udp Xerox [144,SXA]s-net166/tcp Sirius Systems [BXL]s-net166/udp Sirius Systems [BXL]namp167/tcp NAMP [MS9]namp167/udp NAMP [MS9]rsvd168/tcp RSVD [NT12]rsvd168/udp RSVD [NT12]send169/tcp SEND [WDW11]send169/udp SEND [WDW11]print-srv 170/tcp Network PostScript [BKR]print-srv 170/udp Network PostScript [BKR]multiplex 171/tcp Network Innovations Multiplex [KXD]multiplex 171/udp Network Innovations Multiplex [KXD]cl/1172/tcp Network Innovations CL/1 [KXD]cl/1172/udp Network Innovations CL/1 [KXD]xyplex-mux 173/tcp Xyplex [BXS]xyplex-mux 173/udp Xyplex [BXS]mailq174/tcp MAILQ [RXZ]mailq174/udp MAILQ [RXZ]vmnet175/tcp VMNET [CXT]vmnet175/udp VMNET [CXT]genrad-mux 176/tcp GENRAD-MUX [RXT]genrad-mux 176/udp GENRAD-MUX [RXT]xdmcp177/tcp X Display Manager Control Protocol [RWS4]xdmcp177/udp X Display Manager Control Protocol [RWS4]NextStep 178/udp nextstep NeXTStep NextStep Window Servernextstep 178/tcp NextStep NeXTStep NextStep Window Serverbgp179/tcp Border Gateway Protocol [KSL]bgp179/udp Border Gateway Protocol [KSL]ris180/tcp Intergraph [DXB]ris180/udp Intergraph [DXB]unify181/tcp Unify [VXS]unify181/udp Unify [VXS]audit182/tcp Unisys Audit SITP [GXG]audit182/udp Unisys Audit SITP [GXG]ocbinder 183/tcp OCBinder [JXO1]ocbinder 183/udp OCBinder [JXO1]ocserver 184/tcp OCServer [JXO1]ocserver 184/udp OCServer [JXO1]remote-kis 185/tcp Remote-KIS [RXD1]remote-kis 185/udp Remote-KIS [RXD1]kis186/tcp KIS Protocol [RXD1]kis186/udp KIS Protocol [RXD1]aci187/tcp Application Communication Interface [RXC1]aci187/udp Application Communication Interface [RXC1]mumps188/tcp Plus Five's MUMPS [HS23]mumps188/udp Plus Five's MUMPS [HS23]qft189/tcp Queued File Transport [WXS]qft189/udp Queued File Transport [WXS]cacp190/udp Gateway Access Control Protocolgacp190/tcp Gateway Access Control Protocolprospero 191/tcp Prospero Directory Serviceprospero 191/udp Prospero Directory Serviceosu-nms192/tcp OSU Network Monitoring System [DXK]osu-nms192/udp OSU Network Monitoring System [DXK]srmp193/tcp Spider Remote Monitoring Protocol [TXS]srmp193/udp Spider Remote Monitoring Protocol [TXS]irc194/tcp Internet Relay Chat Protocol [JXO2]irc194/udp Internet Relay Chat Protocol [JXO2]dn6-nlm-aud 195/tcp DNSIX Network Level Module Audit [LL69]dn6-nlm-aud 195/udp DNSIX Network Level Module Audit [LL69]dn6-smm-red 196/tcp DNSIX Session Mgt Module Audit Redir[LL69]dn6-smm-red 196/udp DNSIX Session Mgt Module Audit Redir[LL69]dls197/tcp Directory Location Service [SXB]dls197/udp Directory Location Service [SXB]dls-mon198/tcp Directory Location Service Monitor [SXB]dls-mon198/udp Directory Location Service Monitor [SXB]smux199/tcp SMUX [MTR]smux199/udp SMUX [MTR]src200/tcp IBM System Resource Controller [GXM]src200/udp IBM System Resource Controller [GXM]at-rtmp201/tcp AppleTalk Routing Maintenance [RXC]at-rtmp201/udp AppleTalk Routing Maintenance [RXC]at-nbp202/tcp AppleTalk Name Binding [RXC]at-nbp202/udp AppleTalk Name Binding [RXC]at-3203/tcp AppleTalk Unused [RXC]at-3203/udp AppleTalk Unused [RXC]at-echo204/tcp AppleTalk Echo [RXC]at-echo204/udp AppleTalk Echo [RXC]at-5205/tcp AppleTalk Unused [RXC]at-5205/udp AppleTalk Unused [RXC]at-zis206/tcp AppleTalk Zone Information [RXC]at-zis206/udp AppleTalk Zone Information [RXC]at-7207/tcp AppleTalk Unused [RXC]at-7207/udp AppleTalk Unused [RXC]at-8208/tcp AppleTalk Unused [RXC]at-8208/udp AppleTalk Unused [RXC]tam209/tcp Trivial Authenticated Mail Protocol [DXB1]tam209/udp Trivial Authenticated Mail Protocol [DXB1]z39.50210/tcp ANSI Z39.50 [MXN]z39.50210/udp ANSI Z39.50 [MXN]914c/g211/tcp Texas Instruments 914C/G Terminal [BXH1]914c/g211/udp Texas Instruments 914C/G Terminal [BXH1]anet212/tcp ATEXSSTR [JXT]anet212/udp ATEXSSTR [JXT]ipx213/tcp IPX [DP666]ipx213/udp IPX [DP666]vmpwscs214/tcp VM PWSCS [DXS]vmpwscs214/udp VM PWSCS [DXS]softpc215/tcp Insignia Solutions [MXT]softpc215/udp Insignia Solutions [MXT]atls216/tcp Access Technology License Server [LXD]atls216/udp Access Technology License Server [LXD]dbase217/tcp dBASE Unix [DXG1]dbase217/udp dBASE Unix [DXG1]mpp218/tcp Netix Message Posting Protocol [STY]mpp218/udp Netix Message Posting Protocol [STY]uarps219/tcp Unisys ARPs [AXM1]uarps219/udp Unisys ARPs [AXM1]imap3220/tcp Interactive Mail Access Protocol v3 [JXR2]imap3220/udp Interactive Mail Access Protocol v3 [JXR2]fln-spx221/tcp Berkeley rlogind with SPX auth [KXA]fln-spx221/udp Berkeley rlogind with SPX auth [KXA]fsh-spx222/tcp Berkeley rshd with SPX auth [KXA]fsh-spx222/udp Berkeley rshd with SPX auth [KXA]rsh-spx222/tcp Berkeley rshd with SPX authrsh-spx222/udp Berkeley rshd with SPX authcdc223/tcp Certificate Distribution Center [KXA]cdc223/udp Certificate Distribution Center [KXA]sur-meas 243/tcp Survey Measurement [6,DDC1]sur-meas 243/udp Survey Measurement [6,DDC1]link245/tcp LINK [1,RDB2]link245/udp LINK [1,RDB2]dsp3270246/tcp Display Systems Protocol [39,WJS1]dsp3270246/udp Display Systems Protocol [39,WJS1]pdap344/tcp Prospero Data Access Protocol pdap344/udp Pros
文件,检查是否正常传输 udp是面向非连接的不可靠的协议,适用于传输一次性小批量的文件,不对传输数据报进行检查tcp需要先建立连接才能通话udp不需要,实时性要高点tcp可以形象比喻为打电话的过程,udp可以比喻为发短信的过程tcp不能发送广播和组播,只能单播udp可以广播和组播以上是个人所知,描述不够详尽 可以看看这个
