Appendix A. Common Ports and Message Types
In this appendix, I list useful TCP and UDP ports, along with ICMP message types.1 Nmap’s nmap-services file is also a good reference, listing known backdoors and unregistered services.
TCP Ports
Table A-1 lists common TCP ports and references to chapters where applicable.
| Number | Name | Description | Chapter |
|---|---|---|---|
| 21 | ftp | File Transfer Protocol (FTP) | Chapter 7 |
| 22 | ssh | Secure Shell (SSH) | Chapter 7 |
| 23 | telnet | Telnet service | Chapter 7 |
| 25 | smtp | Simple Mail Transfer Protocol (SMTP) | Chapter 9 |
| 43 | whois | WHOIS service | Chapter 4 |
| 53 | domain | Domain Name Service (DNS) | Chapter 4 |
| 79 | finger | Finger service | – |
| 80 | http | Hypertext Transfer Protocol (HTTP) | Chapter 13 |
| 88 | kerberos | Kerberos authentication service | Chapter 7 |
| 110 | pop3 | Post Office Protocol (POP3) | Chapter 9 |
| 111 | sunrpc | RPC portmapper (also known as rpcbind) | Chapter 7 |
| 113 | auth | Authentication service (also known as identd) | – |
| 119 | nntp | Network News Transfer Protocol (NNTP) | – |
| 135 | loc-srv | Microsoft RPC server service | Chapter 8 |
| 139 | netbios-ssn | Microsoft NetBIOS session service | Chapter 8 |
| 143 | imap | Internet Message Access Protocol (IMAP) | Chapter 9 |
| 179 | bgp | Border Gateway Protocol (BGP) | – |
| 389 | ldap | Lightweight Directory Access Protocol (LDAP) | Chapter 7 |
| 443 | https | TLS-wrapped HTTP web service | Chapter 13 |
| 445 | cifs | SMB Direct | Chapter 8 |
| 464 | kerberos | Kerberos password service | Chapter 7 |
| 465 | smtps | TLS-wrapped SMTP mail service | Chapter 9 |
| 513 | login | Remote login ... |
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