Well-Known Port Numbers

Last Edited




Definition of Well-Known Port Numbers in Network Encyclopedia.

What is Well-known port numbers?

Well-known port numbers are port numbers for Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) that have been assigned to specific TCP/IP applications or services by the Internet Assigned Numbers Authority (IANA). Well-known port numbers are assigned within the range 0 through 1023 and are specified in Request for Comments (RFC) 1060. (The total range of possible port numbers is 0 through 65535.) The following table describes some of the well-known port numbers.

Well-Known Ports
Well-Known Ports


“Registered ports” are port numbers that are not controlled by IANA but that IANA registers to indicate to the Internet community which vendor applications use them. Registered ports range from 1024 through 65535 and can be used by any process or program requesting it if the operating system has not already allocated it for a specific use. Programs and processes that communicate using remote procedure calls (RPCs) often randomly select a registered port for each RPC communication session.

Port Number List

Well-Known Port Numbers

1/tcp, udp TCP Port Service Multiplexer (tcpmux)
2/tcp, udp Management Utility (compressnet)
3/tcp, udp Compression Process (compressnet)
4/tcp, udp Unassigned
5/tcp, udp Remote Job Entry (rje)
6/tcp, udp Unassigned
7/tcp, udp Echo (echo)
8/tcp, udp Unassigned
9/tcp, udp Discard; alias = sink null (discard)
10/tcp, udp Unassigned
11/tcp, udp Active Users; alias = users (systat)
12/tcp, udp Unassigned
13/tcp, udp Daytime (daytime)
14/tcp, udp Unassigned
15/tcp, udp Unassigned (was netstat)
16/tcp, udp Unassigned
17/tcp, udp Quote of the Day; alias = quote (qotd)
18/tcp, udp Message Send Protocol (msp)
19/tcp, udp Character Generator; alias = ttytst source (chargen)
20/tcp, udp File Transfer (default data) (ftp-data)
21/tcp, udp File Transfer (control), connection dialog (ftp)
22/tcp, udp Unassigned
23/tcp, udp Telnet (telnet)
24/tcp, udp Any private mail system
25/tcp, udp Simple Mail Transfer; alias = mail (smtp)
26/tcp, udp Unassigned
27/tcp, udp NSW User System FE (nsw-fe)
28/tcp, udp Unassigned
29/tcp, udp MSG ICP (msg-icp)
30/tcp, udp Unassigned
31/tcp, udp MSG Authentication (msg-auth)
32/tcp, udp Unassigned
33/tcp, udp Display Support Protocol (dsp)
34/tcp, udp Unassigned
35/tcp, udp Any private printer server
36/tcp, udp Unassigned
37/tcp, udp Time; alias = timeserver (time)
38/tcp, udp Unassigned
39/tcp, udp Resource Location Protocol; alias = resource (rlp)
40/tcp, udp Unassigned
41/tcp, udp Graphics (graphics)
42/tcp, udp Host Name Server; alias = nameserver (nameserver)
43/tcp, udp Who Is; alias = nicname (nicname)
44/tcp, udp MPM FLAGS Protocol (mpm-flags)
45/tcp, udp Message Processing Module (mpm)
46/tcp, udp MPM (default send) (mpm-snd)
47/tcp, udp NI FTP (ni-ftp)
48/tcp, udp Unassigned
49/tcp, udp Login Host Protocol (login)
50/tcp, udp Remote Mail Checking Protocol (re-mail-ck)
51/tcp, udp IMP Logical Address Maintenance (la-maint)
52/tcp, udp XNS Time Protocol (xns-time)
53/tcp, udp Domain Name Server (domain)
54/tcp, udp XNS Clearinghouse (xns-ch)
55/tcp, udp ISI Graphics Language (isi-gl)
56/tcp, udp XNS Authentication (xns-auth)
57/tcp, udp Any private terminal access
58/tcp, udp XNS Mail (xns-mail)
59/tcp, udp Any private file service
60/tcp, udp Unassigned
61/tcp, udp NI MAIL (ni-mail)
62/tcp, udp ACA Services (acas)
63/tcp, udp VIA Systems – FTP (via-ftp)
64/tcp, udp Communications Integrator (CI) (covia)
65/tcp, udp TACACS-Database Service (tacacs-ds)
66/tcp, udp Oracle SQL*NET (sql*net)
67/tcp, udp DHCP/BOOTP Protocol Server (bootpc)
68/tcp, udp DHCP/BOOTP Protocol Server (bootpc)
69/tcp, udp Trivial File Transfer (tftp)
70/tcp, udp Gopher (gopher)
71/tcp, udp Remote Job Service (netrjs-1)
72/tcp, udp Remote Job Service (netrjs-2)
73/tcp, udp Remote Job Service (netrjs-3)
74/tcp, udp Remote Job Service (netrjs-4)
75/udp Any private dial-out service
76/tcp, udp Unassigned
77/tcp, udp Any private RJE service
78/tcp, udp Vettcp (vettcp)
79/tcp, udp Finger (finger)
80/tcp, udp World Wide Web HTTP (www)
81/tcp, udp HOSTS2 Name Server (hosts2-ns)
82/tcp, udp XFER Utility (xfer)
83/tcp, udp MIT ML Device (mit-ml-dev)
84/tcp, udp Common Trace Facility (ctf)
85/tcp, udp MIT ML Device (mit-ml-dev)
86/tcp, udp Micro Focus Cobol (mfcobol)
87/tcp, udp Any private terminal link; alias = ttylink
88/tcp, udp Kerberos (kerberos)
89/tcp, udp SU/MIT Telnet Gateway (su-mit-tg)
90/tcp, udp DNSIX Security Attribute Token Map
91/tcp, udp MIT Dover Spooler (mit-dov)
92/tcp, udp Network Printing Protocol (npp)
93/tcp, udp Device Control Protocol (dcp)
94/tcp, udp Tivoli Object Dispatcher (objcall)
95/tcp, udp SUPDUP (supdup)
96/tcp, udp DIXIE Protocol Specification (dixie)
97/tcp, udp Swift Remote Virtual File Protocol (swift-rvf)
98/tcp, udp TAC News (tacnews)
99/tcp, udp Metagram Relay (metagram)
100/tcp (unauthorized use) (newacct)
101/tcp, udp NIC Host Name Server; alias = hostname (hostname)
102/tcp, udp ISO-TSAP (iso-tsap)
103/tcp, udp Genesis Point-to-Point Trans Net; alias = webster (gppitnp)
104/tcp, udp ACR-NEMA Digital Imag. & Comm. 300 (acr-nema)
105/tcp, udp Mailbox Name Nameserver (csnet-ns)
106/tcp, udp 3COM-TSMUX (3com-tsmux)
107/tcp, udp Remote Telnet Service (rtelnet)
108/tcp, udp SNA Gateway Access Server (snagas)
109/tcp, udp Post Office Protocol version 2 (POP2); alias = postoffice (pop2)
110/tcp, udp Post Office Protocol version 3 (POP3); alias = postoffice (pop3)
111/tcp, udp SUN Remote Procedure Call (sunrpc)
112/tcp, udp McIDAS Data Transmission Protocol (mcidas)
113/tcp, udp Authentication Service; alias = authentication (auth)
114/tcp, udp Audio News Multicast (audionews) (audionews)
115/tcp, udp Simple File Transfer Protocol (sftp) (sftp)
116/tcp, udp ANSA REX Notify (ansanotify)
117/tcp, udp UUCP Path Service (uucp-path)
118/tcp, udp SQL Services (sqlserv)
119/tcp, udp Network News Transfer Protocol (NNTP); usenet (nntp)
120/tcp, udp CFDPTKT (cfdptkt)
121/tcp, udp Encore Expedited Remote Pro. Call (erpc) (erpc)
122/tcp, udp SMAKYNET (smakynet)
123/tcp, udp Network Time Protocol; alias = ntpd ntp (ntp)
124/tcp, udp ANSA REX Trader (ansatrader)
125/tcp, udp Locus PC-Interface Net Map Server (locus-map)
126/tcp, udp Unisys Unitary Login (unitary)
127/tcp, udp Locus PC-Interface Conn Server (locus-con)
128/tcp, udp GSS X License Verification (gss-xlicen)
129/tcp, udp Password Generator Protocol (pwdgen)
130/tcp, udp Cisco FNATIVE (cisco-fna) (cisco-fna)
131/tcp, udp Cisco TNATIVE (cisco-tna) (cisco-tna)
132/tcp, udp Cisco SYSMAINT (cisco-sys) (cisco-sys)
133/tcp, udp Statistics Service (statsrv)
134/tcp, udp INGRES-NET Service (ingres-net)
135/tcp, udp Location Service (loc-srv)
136/tcp, udp PROFILE Naming System (profile)
137/tcp, udp NetBIOS Name Service (netbios-ns)
138/tcp, udp NetBIOS Datagram Service (netbios-dgm)
139/tcp, udp NetBIOS Session Service (netbios-ssn)
140/tcp, udp EMFIS Data Service (emfis-data)
141/tcp, udp EMFIS Control Service (emfis-cntl)
142/tcp, udp Britton-Lee IDM (bl-idm)
143/tcp, udp Interim Mail Access Protocol v2 (imap2)
144/tcp, udp NewS; alias = news (news)
145/tcp, udp UAAC Protocol (uaac)
146/tcp, udp ISO-IP0 (iso-ip0)
147/tcp, udp ISO-IP (iso-ip)
148/tcp, udp CRONUS-SUPPORT (cronus)
149/tcp, udp AED 512 Emulation Service (aed-512)
150/tcp, udp SQL-NET (sql-net)
151/tcp, udp HEMS (hems)
152/tcp, udp Background File Transfer Program (bftp)
153/tcp, udp SGMP; alias = sgmp (sgmp)
154/tcp, udp Netscape (netsc-prod)
155/tcp, udp Netscape (netsc-dev)
156/tcp, udp SQL Service (sqlsrv)
157/tcp, udp KNET/VM Command/Message Protocol (knet-cmp)
158/tcp, udp PCMail Server; alias = repository (pcmail-srv)
159/tcp, udp NSS-Routing (nss-routing)
160/tcp, udp SGMP-TRAPS (sgmp-traps)
161/tcp, udp SNMP; alias = snmp (snmp)
162/tcp, udp SNMPTRAP (snmptrap)
163/tcp, udp CMIP/TCP Manager (cmip-man)
164/tcp, udp CMIP/TCP Agent (cmip-agent)
165/tcp, udp Xerox (xns-courier)
166/tcp, udp Sirius Systems (s-net)
167/tcp, udp NAMP (namp)
168/tcp, udp RSVD (rsvd)
169/tcp, udp SEND (send)
170/tcp, udp Network PostScript (print-srv)
171/tcp, udp Network Innovations Multiplex (multiplex)
172/tcp, udp Network Innovations CL/1 (cl/1)
173/tcp, udp Xyplex (xyplex-mux)
174/tcp, udp MAILQ (mailq)
175/tcp, udp VMNET (vmnet)
176/tcp, udp GENRAD-MUX (genrad-mux)
177/tcp, udp X Display Manager Control Protocol (xdmcp)
178/tcp, udp NextStep Window Server (nextstep)
179/tcp, udp Border Gateway Protocol (BGP) (bgp)
180/tcp, udp Intergraph (ris)
181/tcp, udp Unify (unify)
182/tcp, udp Unisys Audit SITP (audit)
183/tcp, udp OCBinder (ocbinder)
184/tcp, udp OCServer (ocserver)
185/tcp, udp Remote-KIS (remote-kis)
186/tcp, udp KIS Protocol (kis)
187/tcp, udp Application Communication Interface (aci)
188/tcp, udp Plus Five’s MUMPS (mumps)
189/tcp, udp Queued File Transport (qft)
190/tcp, udp Gateway Access Control Protocol (gacp)
191/tcp, udp Prospero (prospero)
192/tcp, udp OSU Network Monitoring System (osu-nms)
193/tcp, udp Spider Remote Monitoring Protocol (srmp)
194/tcp, udp Internet Relay Chat (IRC) Protocol (irc)
195/tcp, udp DNSIX Network Level Module Audit (dn6-nlm-aud)
196/tcp, udp DNSIX Session Mgt Module Audit Redir (dn6-smm-red)
197/tcp, udp Directory Location Service (dls)
198/tcp, udp Directory Location Service Monitor (dls-mon)
199/tcp, udp SMUX (smux)
200/tcp, udp IBM System Resource Controller (src)
201/tcp, udp AppleTalk Routing Maintenance (at-rtmp)
202/tcp, udp AppleTalk Name Binding (at-nbp)
203/tcp, udp AppleTalk Unused (at-3)
204/tcp, udp AppleTalk Echo (at-echo)
205/tcp, udp AppleTalk Unused (at-5)
206/tcp, udp AppleTalk Zone Information (at-zis)
207/tcp, udp AppleTalk Unused (at-7)
208/tcp, udp AppleTalk Unused (at-8)
209/tcp, udp Trivial Authenticated Mail Protocol (tam)
210/tcp, udp ANSI Z39.50 (z39.50)
211/tcp, udp Texas Instruments 914C/G Terminal (914c/g)
212/tcp, udp ATEXSSTR (anet)
213/tcp, udp Internetwork Packet Exchange (IPX) (ipx)
214/tcp, udp VM PWSCS (vmpwscs)
215/tcp, udp Insignia Solutions (softpc)
216/tcp, udp Access Technology License Server (atls)
217/tcp, udp dBASE UNIX (dbase)
218/tcp, udp Netix Message Posting Protocol (mpp)
219/tcp, udp Unisys ARPs (uarps)
220/tcp, udp Interactive Mail Access Protocol v3 (imap3)
221/tcp, udp Berkeley rlogind with SPX auth (fln-spx)
222/tcp, udp Berkeley rshd with SPX auth (fsh-spx)
223/tcp, udp Certificate Distribution Center (cdc)
224–241 Reserved
243/tcp, udp Survey Measurement (sur-meas)
245/tcp, udp LINK (link)
246/tcp, udp Display Systems Protocol (dsp3270)
247–255 Reserved
345/tcp, udp Perf Analysis Workbench (pawserv)
346/tcp, udp Zebra server (zserv)
347/tcp, udp Fatmen Server (fatserv)
371/tcp, udp Clearcase (clearcase)
372/tcp, udp UNIX Listserv (ulistserv)
373/tcp, udp Legent Corporation (legent-1)
374/tcp, udp Legent Corporation (legent-2)
512/tcp print
512/udp biff
513/tcp Remote logon such as Telnet; (login)
513/udp who
514/tcp Like exec, but automatic authentication is performed as for logon server (cmd)
514/udp  (syslog)
515/tcp, udp Spooler; spooler
517/tcp, udp talk
518/tcp, udp  (ntalk)
519/tcp, udp Unixtime (utime)
520/tcp Extended filename server (efs)
520/udp Local routing process (on site); router routed
525/tcp, udp Timeserver (timed)
526/tcp, udp Newdate (tempo)
530/tcp, udp RPC (courier)
531/tcp Chat (conference)
531/udp MIT disk (rvd-control)
532/tcp, udp Readnews (netnews)
533/tcp, udp For emergency broadcasts (netwall)
540/tcp, udp Uucpd (uucp)
543/tcp, udp  (klogin)
544/tcp, udp Krcmd; alias = cmd (kshell)
550/tcp, udp New-who (new-rwho)
555/tcp, udp  (dsf)
556/tcp, udp Rfs server; alias = rfs_server rfs (remotefs)
560/tcp, udp Rmonitord (rmonitor)
561/tcp, udp  (monitor)
562/tcp, udp Chcmd (chshell)
564/tcp, udp Plan 9 file service (9pfs)
565/tcp, udp Whoami (whoami)
570/tcp, udp Demon (meter)
571/tcp, udp Udemon (meter)
600/tcp, udp Sun IPC server (ipcserver)
607/tcp, udp Nqs (nqs)
666/tcp, udp Reserved for Id software (doom)
704/tcp, udp Errlog copy/server daemon (elcsd)
721–731/tcp printer
740/tcp, udp NETscout Control Protocol (netcp)
741/tcp, udp NetGW (netgw)
742/tcp, udp Network-based Rev. Cont. Sys. (netrcs)
744/tcp, udp Flexible License Manager (flexlm)
747/tcp, udp Fujitsu Device Control (fujitsu-dev)
748/tcp, udp Russell Info Sci Calendar Manager (ris-cm)
749/tcp, udp Kerberos administration (kerberos-adm)
750/tcp Kerberos authentication; alias = kdc (rfile)
750/udp  (loadav)
751/tcp, udp Kerberos authentication (pump)
752/tcp, udp Kerberos password server (qrh)
753/tcp, udp Kerberos userreg server (rrh)
754/tcp, udp Send; Kerberos slave propagation (tell)
758/tcp, udp  (nlogin)
759/tcp, udp  (con)
760/tcp, udp  (ns)
761/tcp, udp  (rxe)
762/tcp, udp  (quotad)
763/tcp, udp  (cycleserv)
764/tcp, udp  (omserv)
765/tcp, udp  (webster)
767/tcp, udp Phone (phonebook)
769/tcp, udp  (vid)
770/tcp, udp  (cadlock)
771/tcp, udp  (rtip)
772/tcp, udp  (cycleserv2)
773/tcp  (submit)
773/udp  (notify)
774/tcp  (rpasswd)
774/udp  (acmaint_dbd)
775/tcp  (entomb)
775/udp  (acmaint_transd)
776/tcp, udp  (wpages)
780/tcp, udp  (wpgs)
781/tcp, udp HP performance data collector (hp-collector)
782/tcp, udp HP performance data managed node (hp-managed-node)
783/tcp, udp HP performance data alarm manager (hp-alarm-mgr)
800/tcp, udp  (mdbs_daemon)
801/tcp, udp  (device)
888/tcp Logon and environment passing (erlogin)
996/tcp, udp XTREE License Server (xtreelic)
997/tcp, udp  (maitrd)
998/tcp  (busboy)
998/udp  (puparp)
999/tcp  (garcon)
999/udp Applix ac (applix)
999/tcp, udp  (puprouter)
1000/tcp  (cadlock)
1000/udp  (ock)