# Common Network Port Numbers Flashcards: Protocols, TCP/UDP & Uses ![A central network gateway with glowing ports connected to web, mail, server, database, user, and security nodes\.]() Study 88 cards on common network ports, TCP/UDP transports, service uses, port ranges, and practical protocol distinctions\. Von [Open Study Contributor]() [Mit diesem Lernkartenset kostenlos lernen]() Nibomo wird geöffnet, damit du mit dem Lernen beginnen kannst\. ## Details zum Lernkartenset - Karten: 88 Karten - Version: 1 - Veröffentlicht: 31. August 2026 - Zuletzt aktualisiert: 10. September 2026 - Lizenz: Common knowledge · CC0 1\.0 - Zielgruppensprachen: [en]() - Fach: Computer networking - Tags: network\-ports ## Über dieses Lernkartenset Build a practical map of common network service ports with 88 independently authored cards. Twelve foundation and distinction cards cover port roles, IANA ranges, independent TCP and UDP namespaces, assignment limits, conventional versus configured ports, client source ports, DNS transport behavior, DHCP endpoints, FTP channels, and common implicit-TLS pairs. The remaining 76 cards practice 38 mappings in both useful directions: service → conventional or registered port, transport, and concise use; and port/transport → service and concise use. Coverage includes FTP control and active-mode data, SSH/SFTP, Telnet, SMTP relay, DNS, DHCPv4 server and client endpoints, TFTP, HTTP, Kerberos, POP3, NTP, the three NetBIOS services, IMAP, SNMP queries and notifications, BGP, LDAP, HTTPS including HTTP/3, direct-hosted SMB, IKE, syslog, SMTP submission, LDAPS, IMAPS, POP3S, Microsoft SQL Server, L2TP, PPTP, RADIUS authentication, MySQL, RDP, IPsec NAT Traversal, SIP, and PostgreSQL. This is a focused recall deck, not a copy of the full IANA registry. It excludes exhaustive assignments, port-scanning or attack instructions, firewall policy, every vendor-specific alternate, dynamic service-discovery inventories, and the claim that a port number proves which application produced observed traffic. Registered, default, conventional, and common-use wording stays explicit because services can be reconfigured or negotiated elsewhere. The sequence establishes the port model first, then mixes web, email, infrastructure, remote-access, file-transfer, network-management, directory, VPN, voice, Windows, and database families. Opposite directions for the same mapping stay at least 38 intervening cards apart. Near-duplicate DNS, DHCP, FTP, SNMP, NetBIOS, and IPsec cues keep at least three unrelated cards between them, and the TLS-pair distinction stays at least three unrelated cards from its closest overlapping mapping. The review scheduler handles continued spacing after installation. Open Study Contributor independently authored the prompts, answers, mapping choices, organization, metadata, and cover from common networking knowledge checked against the current IANA Service Name and Transport Protocol Port Number Registry, relevant RFCs, and official vendor documentation. Organization and product names identify protocols, services, or sources only; no affiliation or endorsement is claimed. No competitor card text, certification questions, answer keys, course text, or source prose was copied. The CC0 label applies to the original prompts, answers, organization, metadata, and generated cover to the extent applicable rights exist. It does not claim ownership of protocol facts, standards, organization names, product names, or third-party source material. ## Ähnliche Lernkartensets - [CompTIA Network\+ N10\-009 Flashcards: Concepts, Operations & Troubleshooting]() - [Spanish Numbers 1–100 Flashcards: Complete Two\-Way Deck]() - [Cranial Nerve Flashcards: Names, Numbers, Functions & Tests]() - [U\.S\. Constitutional Amendments Flashcards: All 27 Numbers & Meanings]() - [Pharmacology Drug Class Flashcards: Mechanisms, Uses & Safety Patterns]() - [Periodic Table Flashcards: All 118 Names, Symbols & Atomic Numbers]() ## Karten in diesem Lernkartenset ### Karte 1 **Frage** What does a transport-layer port number identify? **Antwort** An application endpoint within a host for one transport protocol. The IP addresses, transport protocol, and source and destination ports together identify a communication flow. ### Karte 2 **Frage** Are TCP port 53 and UDP port 53 the same port? **Antwort** No. TCP and UDP have independent 16-bit port namespaces, so 53/TCP and 53/UDP are separate transport endpoints. ### Karte 3 **Frage** What is the IANA System Port range? **Antwort** 0–1023. These are also called Well-Known Ports and are assigned by IANA under the stricter System Port procedures. ### Karte 4 **Frage** What is the IANA User Port range? **Antwort** 1024–49151. These are also called Registered Ports and may be assigned by IANA to services. ### Karte 5 **Frage** What is the IANA Dynamic or Private Port range? **Antwort** 49152–65535. IANA does not assign ports in this range; systems commonly use it for temporary or private endpoints. ### Karte 6 **Frage** Does an IANA port assignment prove what observed traffic is—or that it is safe? **Antwort** No. A registration is a naming convention, not traffic identification, authorization, or a security verdict. Verify the actual protocol and context. ### Karte 7 **Frage** Must a service use its registered or conventional port? **Antwort** No. Administrators and applications can choose another port, negotiate one dynamically, or discover it through mechanisms such as DNS SRV records. ### Karte 8 **Frage** What port roles are typical in a client-server connection? **Antwort** The server usually listens on a known destination port, while the client uses a temporary source port. Either side can be configured differently. ### Karte 9 **Frage** SSH and SFTP — common server port and transport? **Antwort** TCP 22. SSH provides encrypted remote access, and SFTP normally runs as a subsystem inside the same SSH connection. ### Karte 10 **Frage** 53/UDP or 53/TCP — which service? **Antwort** DNS. Routine queries often use UDP, while full DNS implementations also support TCP; zone transfers use TCP. ### Karte 11 **Frage** SMTP relay between mail servers — common port and transport? **Antwort** TCP 25. SMTP uses it for server-to-server mail transfer; user mail submission normally uses port 587 or implicit TLS on 465. ### Karte 12 **Frage** HTTP without TLS — conventional port and transport? **Antwort** TCP 80 for conventional HTTP/1.1 and HTTP/2 connections. The service can be configured on another port. ### Karte 13 **Frage** 67/UDP — which DHCPv4 endpoint? **Antwort** The DHCPv4 server endpoint. Clients send server-directed DHCP messages to UDP port 67. ### Karte 14 **Frage** 21/TCP — which service and channel? **Antwort** FTP control. It carries commands and replies; file data uses a separate connection. ### Karte 15 **Frage** SNMP requests and responses — common agent port and transport? **Antwort** UDP 161. Managers commonly send queries to an SNMP agent there; other SNMP transports exist. ### Karte 16 **Frage** 1433/TCP — which database service? **Antwort** Microsoft SQL Server's default instance. TCP 1433 is the default Database Engine port, but named or custom instances may use another port. ### Karte 17 **Frage** 23/TCP — which remote-access protocol? **Antwort** Telnet. It provides a plaintext remote terminal session and does not protect credentials or traffic with encryption. ### Karte 18 **Frage** NTP — usual port and transport? **Antwort** UDP 123. NTP normally uses UDP for time synchronization; IANA also has a TCP 123 registration, but that is not the usual NTP transport. ### Karte 19 **Frage** Why must a general-purpose DNS implementation support both UDP and TCP? **Antwort** UDP handles most routine queries efficiently, while TCP handles cases such as zone transfers and responses that do not fit the chosen UDP path. Both use port 53. ### Karte 20 **Frage** POP3 — conventional port and transport? **Antwort** TCP 110. POP3 retrieves mail; it can upgrade with STLS, while implicit TLS uses TCP 995. ### Karte 21 **Frage** 443/TCP or 443/UDP — which web service? **Antwort** HTTPS. HTTP/1.1 and HTTP/2 normally use TLS over TCP 443; HTTP/3 uses QUIC over UDP 443. ### Karte 22 **Frage** DHCPv4 client endpoint — port and transport? **Antwort** UDP 68. Servers send client-directed DHCPv4 messages to port 68. ### Karte 23 **Frage** 69/UDP — which file-transfer protocol? **Antwort** TFTP. A client sends the initial read or write request to UDP 69; the transfer then continues with a server-selected UDP transfer identifier. ### Karte 24 **Frage** 162/UDP — which network-management traffic? **Antwort** SNMP notifications, traditionally called traps. Notification receivers commonly listen on UDP 162. ### Karte 25 **Frage** MySQL classic protocol — default port and transport? **Antwort** TCP 3306. It is the default for classic MySQL client-server connections and can be reconfigured. ### Karte 26 **Frage** How do FTP control, active-mode data, and passive-mode data ports differ? **Antwort** Control uses TCP 21. The server side of the default active-mode data connection uses TCP 20, while passive mode negotiates another server port. ### Karte 27 **Frage** 3389/TCP or 3389/UDP — which remote-desktop service? **Antwort** Microsoft Remote Desktop Protocol (RDP). TCP and UDP 3389 are the standard defaults, and the listening port can be changed. ### Karte 28 **Frage** Syslog's conventional UDP transport — port? **Antwort** UDP 514. Classic syslog over UDP has no delivery guarantee; TCP 514 is registered to the shell service, not syslog. ### Karte 29 **Frage** How do DHCPv4 server and client ports pair up? **Antwort** UDP 67 is the server port, and UDP 68 is the client port. Client-to-server messages target 67; server-to-client messages target 68. ### Karte 30 **Frage** IMAP — conventional port and transport? **Antwort** TCP 143. IMAP accesses and manages mail on a server; implicit TLS uses TCP 993. ### Karte 31 **Frage** 445/TCP — which file-sharing service? **Antwort** Direct-hosted SMB. Modern SMB servers commonly listen on TCP 445 without the older NetBIOS session layer. ### Karte 32 **Frage** 88/UDP or 88/TCP — which authentication protocol? **Antwort** Kerberos. Clients and Key Distribution Centers support both transports; TCP also handles requests or replies too large for UDP. ### Karte 33 **Frage** FTP's default active-mode data connection — server-side port and transport? **Antwort** TCP 20. This is the server's default source port for active-mode data; passive FTP negotiates another server port. ### Karte 34 **Frage** BGP — standard operational port and transport? **Antwort** TCP 179. RFC 4271 defines BGP peer sessions over TCP; IANA separately retains a UDP 179 registry entry. ### Karte 35 **Frage** 5432/TCP — which database service? **Antwort** PostgreSQL. TCP 5432 is the customary default server port, but an installation can choose another port. ### Karte 36 **Frage** IKE for IPsec — initial port and transport? **Antwort** UDP 500. IKE normally begins there; NAT traversal commonly moves subsequent IKE and encapsulated ESP traffic to UDP 4500. ### Karte 37 **Frage** NetBIOS Name Service — common port and transport? **Antwort** UDP 137. It supports NetBIOS name registration and lookup; direct-hosted modern SMB does not require it. ### Karte 38 **Frage** 587/TCP — which email role? **Antwort** SMTP message submission. Mail clients normally submit outgoing mail to a submission server there, often with STARTTLS; server relay remains on TCP 25. ### Karte 39 **Frage** 389/TCP — which directory protocol? **Antwort** LDAP. Ordinary connection-oriented LDAP commonly uses TCP 389; IANA also registers UDP 389 for connectionless LDAP. ### Karte 40 **Frage** L2TP — common port and transport? **Antwort** UDP 1701. L2TP carries tunnel control and data but does not provide encryption by itself; deployments often pair it with IPsec. ### Karte 41 **Frage** 138/UDP — which NetBIOS service? **Antwort** NetBIOS Datagram Service. It carries connectionless NetBIOS datagrams, historically used in NetBIOS over TCP/IP environments. ### Karte 42 **Frage** IMAPS — default port and transport? **Antwort** TCP 993. It starts IMAP with an immediate TLS handshake for encrypted mail access. ### Karte 43 **Frage** 636/TCP — which directory-service convention? **Antwort** LDAPS, the commonly used implicit-TLS port for LDAP. LDAP can also negotiate TLS on TCP 389. ### Karte 44 **Frage** 1723/TCP — which VPN control protocol? **Antwort** PPTP control. PPTP uses TCP 1723 for control, while tunneled PPP data travels in GRE—not on TCP or UDP port 47. ### Karte 45 **Frage** NetBIOS Session Service — common port and transport? **Antwort** TCP 139. It provides connection-oriented NetBIOS sessions and historically carried SMB before direct-hosted SMB on TCP 445. ### Karte 46 **Frage** 995/TCP — which mail-access service? **Antwort** POP3S. It starts POP3 with an immediate TLS handshake for encrypted mail retrieval. ### Karte 47 **Frage** RADIUS authentication and authorization — standard port and transport? **Antwort** UDP 1812. RADIUS accounting normally uses the separate UDP port 1813. ### Karte 48 **Frage** IPsec NAT Traversal — port and transport? **Antwort** UDP 4500. It carries IKE and UDP-encapsulated ESP when NAT traversal is in use. ### Karte 49 **Frage** 5060/UDP or 5060/TCP — which signaling protocol? **Antwort** SIP. It commonly uses UDP or TCP 5060 for session signaling; SIP over TLS conventionally uses TCP 5061. ### Karte 50 **Frage** Which common dedicated ports distinguish plaintext or STARTTLS-capable services from implicit-TLS variants? **Antwort** HTTP 80 ↔ HTTPS 443; IMAP 143 ↔ IMAPS 993; POP3 110 ↔ POP3S 995; LDAP 389 ↔ LDAPS 636. A port alone does not prove that TLS is configured correctly. ### Karte 51 **Frage** 22/TCP — which secure remote-access service? **Antwort** SSH. It supports encrypted remote login, command execution, tunneling, and file-transfer tools such as SFTP. ### Karte 52 **Frage** DNS — registered port and required general-purpose transports? **Antwort** Port 53 over UDP and TCP. Most ordinary queries start with UDP, while TCP is required for full implementations and used for zone transfers and other larger exchanges. ### Karte 53 **Frage** 25/TCP — which email function? **Antwort** SMTP mail relay and delivery between servers. End-user clients normally submit new mail on TCP 587 or TCP 465 instead. ### Karte 54 **Frage** 80/TCP — which conventional web service? **Antwort** HTTP without TLS. It is the conventional port for HTTP/1.1 and HTTP/2, although servers can listen elsewhere. ### Karte 55 **Frage** DHCPv4 server endpoint — port and transport? **Antwort** UDP 67. DHCPv4 clients direct server-bound messages to that port. ### Karte 56 **Frage** FTP control — server port and transport? **Antwort** TCP 21. Commands and replies use the persistent control connection; data travels on a separate connection. ### Karte 57 **Frage** 161/UDP — which network-management traffic? **Antwort** SNMP requests and responses. Managed agents commonly listen on UDP 161 for manager queries. ### Karte 58 **Frage** Microsoft SQL Server default instance — default port and transport? **Antwort** TCP 1433. Named instances may use dynamic or custom ports, with SQL Server Browser commonly using UDP 1434 for discovery. ### Karte 59 **Frage** Telnet — conventional port and transport? **Antwort** TCP 23. Telnet carries terminal traffic in plaintext, so SSH is the usual secure replacement. ### Karte 60 **Frage** 123/UDP — which time service? **Antwort** NTP. Network Time Protocol commonly synchronizes clocks over UDP 123. ### Karte 61 **Frage** 110/TCP — which mail-access protocol? **Antwort** POP3. It downloads or retrieves mail from a server; implicit TLS uses TCP 995. ### Karte 62 **Frage** HTTPS — common port and transports? **Antwort** Port 443: TCP for HTTP/1.1 and HTTP/2 over TLS, and UDP for HTTP/3 over QUIC. ### Karte 63 **Frage** 68/UDP — which DHCPv4 endpoint? **Antwort** The DHCPv4 client endpoint. Servers direct client-bound DHCP messages to UDP 68. ### Karte 64 **Frage** TFTP — initial request port and transport? **Antwort** UDP 69. Only the initial request targets 69; the server chooses another UDP transfer identifier for the data exchange. ### Karte 65 **Frage** SNMP traps and other notifications — common receiver port and transport? **Antwort** UDP 162. SNMP notification receivers commonly listen there. ### Karte 66 **Frage** 3306/TCP — which database protocol? **Antwort** The classic MySQL protocol. TCP 3306 is its default client-server port and is configurable. ### Karte 67 **Frage** RDP — standard port and transports? **Antwort** TCP and UDP 3389. Microsoft Remote Desktop uses them by default, though administrators can change the listening port. ### Karte 68 **Frage** 514/UDP — which logging protocol? **Antwort** Syslog over UDP. It is a conventional lightweight transport without delivery guarantees; secure syslog commonly uses another transport and port. ### Karte 69 **Frage** 143/TCP — which mail-access protocol? **Antwort** IMAP. It manages mail on the server; implicit TLS uses TCP 993. ### Karte 70 **Frage** Direct-hosted SMB — common server port and transport? **Antwort** TCP 445. It carries SMB directly over TCP without the legacy NetBIOS Session Service on TCP 139. ### Karte 71 **Frage** Kerberos KDC traffic — port and transports? **Antwort** UDP and TCP 88. Conforming clients and Key Distribution Centers support both, with TCP available for larger exchanges. ### Karte 72 **Frage** 20/TCP — which FTP role? **Antwort** The server side of FTP's default active-mode data connection. Passive mode negotiates a different server port. ### Karte 73 **Frage** 179/TCP — which routing protocol? **Antwort** BGP. Border Gateway Protocol peers use a TCP session to exchange routing information. ### Karte 74 **Frage** PostgreSQL — customary default port and transport? **Antwort** TCP 5432. PostgreSQL servers normally use it unless configured or compiled with another default. ### Karte 75 **Frage** 500/UDP — which IPsec setup protocol? **Antwort** IKE, the Internet Key Exchange protocol. It negotiates IPsec security associations and commonly moves to UDP 4500 when NAT traversal is used. ### Karte 76 **Frage** 137/UDP — which NetBIOS service? **Antwort** NetBIOS Name Service. It handles name registration and lookup in legacy NetBIOS over TCP/IP environments. ### Karte 77 **Frage** SMTP message submission — normal port and transport? **Antwort** TCP 587. It separates authenticated client submission from server-to-server SMTP relay on TCP 25; STARTTLS is commonly used. ### Karte 78 **Frage** LDAP — conventional connection-oriented port and transport? **Antwort** TCP 389. Connectionless LDAP can use UDP 389, and implicit-TLS LDAP commonly uses TCP 636. ### Karte 79 **Frage** 1701/UDP — which tunneling protocol? **Antwort** L2TP. It tunnels Layer 2 traffic but needs a separate security layer such as IPsec when confidentiality is required. ### Karte 80 **Frage** NetBIOS Datagram Service — common port and transport? **Antwort** UDP 138. It provides connectionless NetBIOS datagram delivery. ### Karte 81 **Frage** 993/TCP — which mail-access service? **Antwort** IMAPS. It begins IMAP with implicit TLS for encrypted access to mail stored on a server. ### Karte 82 **Frage** LDAPS — commonly used implicit-TLS port and transport? **Antwort** TCP 636. LDAP can instead use TCP 389 and negotiate TLS with StartTLS. ### Karte 83 **Frage** PPTP control — port and transport? **Antwort** TCP 1723. The control channel uses that port; PPP payloads travel through GRE, which is IP protocol 47 rather than port 47. ### Karte 84 **Frage** 139/TCP — which NetBIOS service? **Antwort** NetBIOS Session Service. It historically carried SMB sessions; direct-hosted SMB commonly uses TCP 445 instead. ### Karte 85 **Frage** POP3S — default port and transport? **Antwort** TCP 995. It uses implicit TLS for encrypted POP3 mail retrieval. ### Karte 86 **Frage** 1812/UDP — which AAA service? **Antwort** RADIUS authentication and authorization. RADIUS accounting normally uses UDP 1813. ### Karte 87 **Frage** 4500/UDP — which IPsec function? **Antwort** IPsec NAT Traversal. It carries IKE and UDP-encapsulated ESP across network address translation. ### Karte 88 **Frage** SIP signaling without implicit TLS — common port and transports? **Antwort** UDP or TCP 5060. SIP over TLS conventionally uses TCP 5061, and media streams use separately negotiated ports. --- *[Die gestaltete HTML\-Version dieser Seite ansehen]()* *KI-Agenten können in diesem Dienst ein Benutzerkonto anlegen, beginnend mit `GET https://api.nibomo.com/v1/`. Nach der Einrichtung können sie sich auch über MCP unter `https://mcp.nibomo.com/mcp` verbinden.* *Tipp: Hänge `.md` an jede URL auf https://nibomo.com an, um eine saubere Markdown-Version der Seite zu erhalten.*