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.

Table A-1. Common TCP ports
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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