Common Network Port Numbers Flashcards: Protocols, TCP/UDP & Uses
Study 88 cards on common network ports, TCP/UDP transports, service uses, port ranges, and practical protocol distinctions.
اس ڈیک کے بارے میں
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.
اس ڈیک کے کارڈز
کارڈ 1
سوال
What does a transport-layer port number identify?
جواب
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.
کارڈ 2
سوال
Are TCP port 53 and UDP port 53 the same port?
جواب
No. TCP and UDP have independent 16-bit port namespaces, so 53/TCP and 53/UDP are separate transport endpoints.
کارڈ 3
سوال
What is the IANA System Port range?
جواب
0–1023. These are also called Well-Known Ports and are assigned by IANA under the stricter System Port procedures.
کارڈ 4
سوال
What is the IANA User Port range?
جواب
1024–49151. These are also called Registered Ports and may be assigned by IANA to services.
کارڈ 5
سوال
What is the IANA Dynamic or Private Port range?
جواب
49152–65535. IANA does not assign ports in this range; systems commonly use it for temporary or private endpoints.
کارڈ 6
سوال
Does an IANA port assignment prove what observed traffic is—or that it is safe?
جواب
No. A registration is a naming convention, not traffic identification, authorization, or a security verdict. Verify the actual protocol and context.
کارڈ 7
سوال
Must a service use its registered or conventional port?
جواب
No. Administrators and applications can choose another port, negotiate one dynamically, or discover it through mechanisms such as DNS SRV records.
کارڈ 8
سوال
What port roles are typical in a client-server connection?
جواب
The server usually listens on a known destination port, while the client uses a temporary source port. Either side can be configured differently.
کارڈ 9
سوال
SSH and SFTP — common server port and transport?
جواب
TCP 22. SSH provides encrypted remote access, and SFTP normally runs as a subsystem inside the same SSH connection.
کارڈ 10
سوال
53/UDP or 53/TCP — which service?
جواب
DNS. Routine queries often use UDP, while full DNS implementations also support TCP; zone transfers use TCP.
کارڈ 11
سوال
SMTP relay between mail servers — common port and transport?
جواب
TCP 25. SMTP uses it for server-to-server mail transfer; user mail submission normally uses port 587 or implicit TLS on 465.
کارڈ 12
سوال
HTTP without TLS — conventional port and transport?
جواب
TCP 80 for conventional HTTP/1.1 and HTTP/2 connections. The service can be configured on another port.
کارڈ 13
سوال
67/UDP — which DHCPv4 endpoint?
جواب
The DHCPv4 server endpoint. Clients send server-directed DHCP messages to UDP port 67.
کارڈ 14
سوال
21/TCP — which service and channel?
جواب
FTP control. It carries commands and replies; file data uses a separate connection.
کارڈ 15
سوال
SNMP requests and responses — common agent port and transport?
جواب
UDP 161. Managers commonly send queries to an SNMP agent there; other SNMP transports exist.
کارڈ 16
سوال
1433/TCP — which database service?
جواب
Microsoft SQL Server's default instance. TCP 1433 is the default Database Engine port, but named or custom instances may use another port.
کارڈ 17
سوال
23/TCP — which remote-access protocol?
جواب
Telnet. It provides a plaintext remote terminal session and does not protect credentials or traffic with encryption.
کارڈ 18
سوال
NTP — usual port and transport?
جواب
UDP 123. NTP normally uses UDP for time synchronization; IANA also has a TCP 123 registration, but that is not the usual NTP transport.
کارڈ 19
سوال
Why must a general-purpose DNS implementation support both UDP and TCP?
جواب
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.
کارڈ 20
سوال
POP3 — conventional port and transport?
جواب
TCP 110. POP3 retrieves mail; it can upgrade with STLS, while implicit TLS uses TCP 995.
کارڈ 21
سوال
443/TCP or 443/UDP — which web service?
جواب
HTTPS. HTTP/1.1 and HTTP/2 normally use TLS over TCP 443; HTTP/3 uses QUIC over UDP 443.
کارڈ 22
سوال
DHCPv4 client endpoint — port and transport?
جواب
UDP 68. Servers send client-directed DHCPv4 messages to port 68.
کارڈ 23
سوال
69/UDP — which file-transfer protocol?
جواب
TFTP. A client sends the initial read or write request to UDP 69; the transfer then continues with a server-selected UDP transfer identifier.
کارڈ 24
سوال
162/UDP — which network-management traffic?
جواب
SNMP notifications, traditionally called traps. Notification receivers commonly listen on UDP 162.
کارڈ 25
سوال
MySQL classic protocol — default port and transport?
جواب
TCP 3306. It is the default for classic MySQL client-server connections and can be reconfigured.
کارڈ 26
سوال
How do FTP control, active-mode data, and passive-mode data ports differ?
جواب
Control uses TCP 21. The server side of the default active-mode data connection uses TCP 20, while passive mode negotiates another server port.
کارڈ 27
سوال
3389/TCP or 3389/UDP — which remote-desktop service?
جواب
Microsoft Remote Desktop Protocol (RDP). TCP and UDP 3389 are the standard defaults, and the listening port can be changed.
کارڈ 28
سوال
Syslog's conventional UDP transport — port?
جواب
UDP 514. Classic syslog over UDP has no delivery guarantee; TCP 514 is registered to the shell service, not syslog.
کارڈ 29
سوال
How do DHCPv4 server and client ports pair up?
جواب
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.
کارڈ 30
سوال
IMAP — conventional port and transport?
جواب
TCP 143. IMAP accesses and manages mail on a server; implicit TLS uses TCP 993.
کارڈ 31
سوال
445/TCP — which file-sharing service?
جواب
Direct-hosted SMB. Modern SMB servers commonly listen on TCP 445 without the older NetBIOS session layer.
کارڈ 32
سوال
88/UDP or 88/TCP — which authentication protocol?
جواب
Kerberos. Clients and Key Distribution Centers support both transports; TCP also handles requests or replies too large for UDP.
کارڈ 33
سوال
FTP's default active-mode data connection — server-side port and transport?
جواب
TCP 20. This is the server's default source port for active-mode data; passive FTP negotiates another server port.
کارڈ 34
سوال
BGP — standard operational port and transport?
جواب
TCP 179. RFC 4271 defines BGP peer sessions over TCP; IANA separately retains a UDP 179 registry entry.
کارڈ 35
سوال
5432/TCP — which database service?
جواب
PostgreSQL. TCP 5432 is the customary default server port, but an installation can choose another port.
کارڈ 36
سوال
IKE for IPsec — initial port and transport?
جواب
UDP 500. IKE normally begins there; NAT traversal commonly moves subsequent IKE and encapsulated ESP traffic to UDP 4500.
کارڈ 37
سوال
NetBIOS Name Service — common port and transport?
جواب
UDP 137. It supports NetBIOS name registration and lookup; direct-hosted modern SMB does not require it.
کارڈ 38
سوال
587/TCP — which email role?
جواب
SMTP message submission. Mail clients normally submit outgoing mail to a submission server there, often with STARTTLS; server relay remains on TCP 25.
کارڈ 39
سوال
389/TCP — which directory protocol?
جواب
LDAP. Ordinary connection-oriented LDAP commonly uses TCP 389; IANA also registers UDP 389 for connectionless LDAP.
کارڈ 40
سوال
L2TP — common port and transport?
جواب
UDP 1701. L2TP carries tunnel control and data but does not provide encryption by itself; deployments often pair it with IPsec.
کارڈ 41
سوال
138/UDP — which NetBIOS service?
جواب
NetBIOS Datagram Service. It carries connectionless NetBIOS datagrams, historically used in NetBIOS over TCP/IP environments.
کارڈ 42
سوال
IMAPS — default port and transport?
جواب
TCP 993. It starts IMAP with an immediate TLS handshake for encrypted mail access.
کارڈ 43
سوال
636/TCP — which directory-service convention?
جواب
LDAPS, the commonly used implicit-TLS port for LDAP. LDAP can also negotiate TLS on TCP 389.
کارڈ 44
سوال
1723/TCP — which VPN control protocol?
جواب
PPTP control. PPTP uses TCP 1723 for control, while tunneled PPP data travels in GRE—not on TCP or UDP port 47.
کارڈ 45
سوال
NetBIOS Session Service — common port and transport?
جواب
TCP 139. It provides connection-oriented NetBIOS sessions and historically carried SMB before direct-hosted SMB on TCP 445.
کارڈ 46
سوال
995/TCP — which mail-access service?
جواب
POP3S. It starts POP3 with an immediate TLS handshake for encrypted mail retrieval.
کارڈ 47
سوال
RADIUS authentication and authorization — standard port and transport?
جواب
UDP 1812. RADIUS accounting normally uses the separate UDP port 1813.
کارڈ 48
سوال
IPsec NAT Traversal — port and transport?
جواب
UDP 4500. It carries IKE and UDP-encapsulated ESP when NAT traversal is in use.
کارڈ 49
سوال
5060/UDP or 5060/TCP — which signaling protocol?
جواب
SIP. It commonly uses UDP or TCP 5060 for session signaling; SIP over TLS conventionally uses TCP 5061.
کارڈ 50
سوال
Which common dedicated ports distinguish plaintext or STARTTLS-capable services from implicit-TLS variants?
جواب
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.
کارڈ 51
سوال
22/TCP — which secure remote-access service?
جواب
SSH. It supports encrypted remote login, command execution, tunneling, and file-transfer tools such as SFTP.
کارڈ 52
سوال
DNS — registered port and required general-purpose transports?
جواب
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.
کارڈ 53
سوال
25/TCP — which email function?
جواب
SMTP mail relay and delivery between servers. End-user clients normally submit new mail on TCP 587 or TCP 465 instead.
کارڈ 54
سوال
80/TCP — which conventional web service?
جواب
HTTP without TLS. It is the conventional port for HTTP/1.1 and HTTP/2, although servers can listen elsewhere.
کارڈ 55
سوال
DHCPv4 server endpoint — port and transport?
جواب
UDP 67. DHCPv4 clients direct server-bound messages to that port.
کارڈ 56
سوال
FTP control — server port and transport?
جواب
TCP 21. Commands and replies use the persistent control connection; data travels on a separate connection.
کارڈ 57
سوال
161/UDP — which network-management traffic?
جواب
SNMP requests and responses. Managed agents commonly listen on UDP 161 for manager queries.
کارڈ 58
سوال
Microsoft SQL Server default instance — default port and transport?
جواب
TCP 1433. Named instances may use dynamic or custom ports, with SQL Server Browser commonly using UDP 1434 for discovery.
کارڈ 59
سوال
Telnet — conventional port and transport?
جواب
TCP 23. Telnet carries terminal traffic in plaintext, so SSH is the usual secure replacement.
کارڈ 60
سوال
123/UDP — which time service?
جواب
NTP. Network Time Protocol commonly synchronizes clocks over UDP 123.
کارڈ 61
سوال
110/TCP — which mail-access protocol?
جواب
POP3. It downloads or retrieves mail from a server; implicit TLS uses TCP 995.
کارڈ 62
سوال
HTTPS — common port and transports?
جواب
Port 443: TCP for HTTP/1.1 and HTTP/2 over TLS, and UDP for HTTP/3 over QUIC.
کارڈ 63
سوال
68/UDP — which DHCPv4 endpoint?
جواب
The DHCPv4 client endpoint. Servers direct client-bound DHCP messages to UDP 68.
کارڈ 64
سوال
TFTP — initial request port and transport?
جواب
UDP 69. Only the initial request targets 69; the server chooses another UDP transfer identifier for the data exchange.
کارڈ 65
سوال
SNMP traps and other notifications — common receiver port and transport?
جواب
UDP 162. SNMP notification receivers commonly listen there.
کارڈ 66
سوال
3306/TCP — which database protocol?
جواب
The classic MySQL protocol. TCP 3306 is its default client-server port and is configurable.
کارڈ 67
سوال
RDP — standard port and transports?
جواب
TCP and UDP 3389. Microsoft Remote Desktop uses them by default, though administrators can change the listening port.
کارڈ 68
سوال
514/UDP — which logging protocol?
جواب
Syslog over UDP. It is a conventional lightweight transport without delivery guarantees; secure syslog commonly uses another transport and port.
کارڈ 69
سوال
143/TCP — which mail-access protocol?
جواب
IMAP. It manages mail on the server; implicit TLS uses TCP 993.
کارڈ 70
سوال
Direct-hosted SMB — common server port and transport?
جواب
TCP 445. It carries SMB directly over TCP without the legacy NetBIOS Session Service on TCP 139.
کارڈ 71
سوال
Kerberos KDC traffic — port and transports?
جواب
UDP and TCP 88. Conforming clients and Key Distribution Centers support both, with TCP available for larger exchanges.
کارڈ 72
سوال
20/TCP — which FTP role?
جواب
The server side of FTP's default active-mode data connection. Passive mode negotiates a different server port.
کارڈ 73
سوال
179/TCP — which routing protocol?
جواب
BGP. Border Gateway Protocol peers use a TCP session to exchange routing information.
کارڈ 74
سوال
PostgreSQL — customary default port and transport?
جواب
TCP 5432. PostgreSQL servers normally use it unless configured or compiled with another default.
کارڈ 75
سوال
500/UDP — which IPsec setup protocol?
جواب
IKE, the Internet Key Exchange protocol. It negotiates IPsec security associations and commonly moves to UDP 4500 when NAT traversal is used.
کارڈ 76
سوال
137/UDP — which NetBIOS service?
جواب
NetBIOS Name Service. It handles name registration and lookup in legacy NetBIOS over TCP/IP environments.
کارڈ 77
سوال
SMTP message submission — normal port and transport?
جواب
TCP 587. It separates authenticated client submission from server-to-server SMTP relay on TCP 25; STARTTLS is commonly used.
کارڈ 78
سوال
LDAP — conventional connection-oriented port and transport?
جواب
TCP 389. Connectionless LDAP can use UDP 389, and implicit-TLS LDAP commonly uses TCP 636.
کارڈ 79
سوال
1701/UDP — which tunneling protocol?
جواب
L2TP. It tunnels Layer 2 traffic but needs a separate security layer such as IPsec when confidentiality is required.
کارڈ 80
سوال
NetBIOS Datagram Service — common port and transport?
جواب
UDP 138. It provides connectionless NetBIOS datagram delivery.
کارڈ 81
سوال
993/TCP — which mail-access service?
جواب
IMAPS. It begins IMAP with implicit TLS for encrypted access to mail stored on a server.
کارڈ 82
سوال
LDAPS — commonly used implicit-TLS port and transport?
جواب
TCP 636. LDAP can instead use TCP 389 and negotiate TLS with StartTLS.
کارڈ 83
سوال
PPTP control — port and transport?
جواب
TCP 1723. The control channel uses that port; PPP payloads travel through GRE, which is IP protocol 47 rather than port 47.
کارڈ 84
سوال
139/TCP — which NetBIOS service?
جواب
NetBIOS Session Service. It historically carried SMB sessions; direct-hosted SMB commonly uses TCP 445 instead.
کارڈ 85
سوال
POP3S — default port and transport?
جواب
TCP 995. It uses implicit TLS for encrypted POP3 mail retrieval.
کارڈ 86
سوال
1812/UDP — which AAA service?
جواب
RADIUS authentication and authorization. RADIUS accounting normally uses UDP 1813.
کارڈ 87
سوال
4500/UDP — which IPsec function?
جواب
IPsec NAT Traversal. It carries IKE and UDP-encapsulated ESP across network address translation.
کارڈ 88
سوال
SIP signaling without implicit TLS — common port and transports?
جواب
UDP or TCP 5060. SIP over TLS conventionally uses TCP 5061, and media streams use separately negotiated ports.
88 کارڈز
Common Network Port Numbers Flashcards: Protocols, TCP/UDP & Uses
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