| Port | | Description |
| 0 | | Reserved |
| 1 | | tcpmux |
| 3 | | Compression Process |
| 4 | | |
| 5 | | Remote Job Entry (rje) |
| 7 | | echo |
| 9 | | discard |
| 11 | | systat |
| 13 | | daytime |
| 15 | | netstat |
| 17 | | qotd |
| 18 | | send/rwp |
| 19 | | chargen |
| 20 | | ftp-data |
| 21 | | ftp |
| 22 | | ssh, pcAnywhere |
| 23 | | Telnet |
| 24 | | any private mail system |
| 25 | | SMTP |
| 27 | | ETRN |
| 29 | | msg-icp |
| 31 | | msg-auth |
| 33 | | dsp |
| 35 | | any private printer server |
| 37 | | time |
| 38 | | RAP |
| 39 | | Resource Location Protocol (rlp) |
| 40 | | |
| 41 | | Graphics |
| 42 | | nameserv, WINS |
| 43 | | whois, nickname |
| 44 | | MPM FLAGS Protocol |
| 45 | | Message Processing Module [recv] |
| 46 | | MPM [default send] |
| 47 | | NI FTP |
| 48 | | Digital Audit Daemon |
| 49 | | TACACS, Login Host Protocol |
| 50 | | RMCP, re-mail-ck |
| 51 | | UDP. IMP Logical Address Maintenance |
| 52 | | XNS Time Protocol |
| 53 | | DNS |
| 54 | | XNS Clearinghouse |
| 55 | | ISI Graphics Language |
| 56 | | XNS Authentication |
| 57 | | MTP |
| 58 | | XNS Mail |
| 59 | | NFILE |
| 60 | | |
| 61 | | NI MAIL |
| 62 | | ACA Services |
| 63 | | whois++ |
| 64 | | Communications Integrator (CI) |
| 65 | | TACACS-Database Service |
| 66 | | sql*net |
| 67 | | bootps |
| 68 | | bootpd/dhcp |
| 69 | | Trivial File Transfer Protocol (tftp) |
| 70 | | Gopher |
| 71 | | Remote Job Service |
| 72 | | Remote Job Service |
| 73 | | Remote Job Service |
| 74 | | Remote Job Service |
| 75 | | any private dial out service |
| 76 | | Distributed External Object Store |
| 77 | | any private RJE service |
| 78 | | vettcp |
| 79 | | finger |
| 80 | | www-http |
| 81 | | HOSTS2 Name Server |
| 82 | | XFER Utility |
| 83 | | MIT ML Device |
| 84 | | Common Trace Facility |
| 85 | | MIT ML Device |
| 86 | | Micro Focus Cobol |
| 87 | | any private terminal link |
| 88 | | Kerberos, WWW |
| 89 | | SU/MIT Telnet Gateway |
| 90 | | DNSIX Securit Attribute Token Map |
| 91 | | MIT Dover Spooler |
| 92 | | Network Printing Protocol |
| 93 | | Device Control Protocol |
| 94 | | Tivoli Object Dispatcher |
| 95 | | SUPDUP |
| 96 | | DIXIE Protocol Specification |
| 97 | | Swift Remote Virtural File Protocol |
| 98 | | TAC News / linuxconf |
| 99 | | Metagram Relay |
| 100 | | [unauthorized use] |
| 101 | | NIC Host Name Server (HOSTNAME) |
| 102 | | ISO-TSAP Class 0 / X.400, ITOT |
| 103 | | Genesis Point-to-Point Trans Net |
| 104 | | ACR-NEMA Digital Imag. & Comm. 300 |
| 105 | | Mailbox Name Nameserver / cso |
| 106 | | 3COM-TSMUX / Password Server (poppassd) |
| 107 | | Remote Telnet Service |
| 108 | | SNA Gateway Access Server |
| 109 | | POP2 |
| 110 | | POP3 |
| 111 | | SUN Remote Procedure Call / Sun RPC Portmapper |
| 112 | | McIDAS Data Transmission Protocol |
| 113 | | iAuthentication Service (dentd/auth) |
| 114 | | Audio News Multicast |
| 115 | | SFTP |
| 116 | | ANSA REX Notify |
| 117 | | UUCP |
| 118 | | SQL Services |
| 119 | | NNTP |
| 120 | | CFDPTKT (CFDP) |
| 121 | |
