Well-known: 0 to 1023
Core Internet services (HTTP, SSH, DNS, SMTP). On Linux and macOS, opening them requires root or a capability.
What Is This Port? TCP & UDP Port Lookup
Look up any port number or service name. Every port comes from the official IANA registry, and the ports attackers scan most come with a risk score, encryption status, known attacks and hardening steps.
Search the port registry
6,119 ports1-25 of 6,119
| Port | Service | Proto | Category | Risk | TLS |
|---|---|---|---|---|---|
| 443 | HTTPShttps | tcp udp sctp | Web | 2/10 low | yes |
| 80 | HTTPhttp, www, www-http | tcp udp sctp | Web | 4/10 moderate | no |
| 22 | SSHssh | tcp udp sctp | Remote access | 5/10 moderate | yes |
| 3389 | RDPms-wbt-server | tcp udp | Remote access | 9/10 critical | yes |
| 445 | SMBmicrosoft-ds | tcp udp | File transfer & sharing | 9/10 critical | optional |
| 53 | DNSdomain | tcp udp | Network services | 4/10 moderate | no |
| 21 | FTPftp | tcp udp sctp | File transfer & sharing | 7/10 high | optional |
| 25 | SMTPsmtp | tcp udp | 4/10 moderate | optional | |
| 8080 | HTTP alternatehttp-alt | tcp udp | Web | 6/10 high | no |
| 23 | Telnettelnet | tcp udp | Remote access | 9/10 critical | no |
| 3306 | MySQL / MariaDBmysql | tcp udp | Databases & caches | 8/10 high | optional |
| 1433 | Microsoft SQL Serverms-sql-s | tcp udp | Databases & caches | 8/10 high | optional |
| 5432 | PostgreSQLpostgresql | tcp udp | Databases & caches | 8/10 high | optional |
| 6379 | Redisredis | tcp | Databases & caches | 9/10 critical | optional |
| 27017 | MongoDBmongodb | tcp | Databases & caches | 9/10 critical | optional |
| 9200 | Elasticsearchwap-wsp | tcp udp | Databases & caches | 9/10 critical | optional |
| 5900 | VNCrfb | tcp udp | Remote access | 9/10 critical | no |
| 139 | NetBIOS Sessionnetbios-ssn | tcp udp | File transfer & sharing | 8/10 high | no |
| 135 | MS RPCepmap | tcp udp | Network services | 8/10 high | no |
| 389 | LDAPldap | tcp udp | Directory & authentication | 6/10 high | optional |
| 636 | LDAPSldaps | tcp udp | Directory & authentication | 5/10 moderate | yes |
| 88 | Kerberoskerberos | tcp udp | Directory & authentication | 6/10 high | yes |
| 5985 | WinRM (HTTP)wsman | tcp udp | Remote access | 8/10 high | optional |
| 5986 | WinRM (HTTPS)wsmans | tcp udp | Remote access | 6/10 high | yes |
| 161 | SNMPsnmp | udp tcp | Monitoring & logging | 7/10 high | no |
// source: IANA service name and port number registry, updated 2026-10-23 · security notes by CyberHunter · data under CC BY 4.0
Most common ports
The ports you meet most in firewall rules, scans and incident reports.
:443 HTTPS tcp · udp · sctp · low risk :80 HTTP tcp · udp · sctp · moderate risk :22 SSH tcp · udp · sctp · moderate risk :3389 RDP tcp · udp · critical risk :445 SMB tcp · udp · critical risk :53 DNS tcp · udp · moderate risk :21 FTP tcp · udp · sctp · high risk :25 SMTP tcp · udp · moderate risk :8080 HTTP alternate tcp · udp · high risk :23 Telnet tcp · udp · critical risk :3306 MySQL / MariaDB tcp · udp · high risk :1433 Microsoft SQL Server tcp · udp · high risk :5432 PostgreSQL tcp · udp · high risk :6379 Redis tcp · critical risk :27017 MongoDB tcp · critical risk :9200 Elasticsearch tcp · udp · critical risk :5900 VNC tcp · udp · critical risk :139 NetBIOS Session tcp · udp · high risk :135 MS RPC tcp · udp · high risk :389 LDAP tcp · udp · high risk :636 LDAPS tcp · udp · moderate risk :88 Kerberos tcp · udp · high risk :5985 WinRM (HTTP) tcp · udp · high risk :5986 WinRM (HTTPS) tcp · udp · high risk
Ports you should never expose to the Internet
Services that are actively exploited or give direct control when reachable from outside.
:2375 Docker API (HTTP) 10/10 critical :502 Modbus TCP 10/10 critical :102 Siemens S7 (ISO-TSAP) 10/10 critical :3389 RDP 9/10 critical :445 SMB 9/10 critical :23 Telnet 9/10 critical :6379 Redis 9/10 critical :27017 MongoDB 9/10 critical :9200 Elasticsearch 9/10 critical :5900 VNC 9/10 critical :10250 Kubelet API 9/10 critical :2379 etcd 9/10 critical
Browse ports by category
Web 130 ports Remote access 58 ports File transfer & sharing 71 ports Email 47 ports Databases & caches 123 ports Directory & authentication 83 ports Network services 199 ports VPN, tunnels & proxies 64 ports Messaging & queues 19 ports Voice & chat 58 ports Media & streaming 71 ports IoT & industrial (ICS) 30 ports DevOps, cloud & containers 86 ports Monitoring & logging 83 ports Gaming 27 ports Other services 4,970 ports
Browse every port by number
Blocks of 1,000 port numbers, each listing all the registered ports it contains.
0-999 681 ports 1000-1999 969 ports 2000-2999 992 ports 3000-3999 985 ports 4000-4999 535 ports 5000-5999 433 ports 6000-6999 262 ports 7000-7999 223 ports 8000-8999 222 ports 9000-9999 195 ports 10000-10999 63 ports 11000-11999 48 ports 12000-12999 25 ports 13000-13999 25 ports 14000-14999 17 ports 15000-15999 11 ports 16000-16999 28 ports 17000-17999 20 ports 18000-18999 22 ports 19000-19999 19 ports 20000-20999 20 ports 21000-21999 16 ports 22000-22999 22 ports 23000-23999 16 ports 24000-24999 25 ports 25000-25999 22 ports 26000-26999 11 ports 27000-27999 11 ports 28000-28999 8 ports 29000-29999 6 ports 30000-30999 11 ports 31000-31999 12 ports 32000-32999 20 ports 33000-33999 10 ports 34000-34999 10 ports 35000-35999 12 ports 36000-36999 13 ports 37000-37999 5 ports 38000-38999 13 ports 39000-39999 2 ports 40000-40999 7 ports 41000-41999 7 ports 42000-42999 4 ports 43000-43999 10 ports 44000-44999 11 ports 45000-45999 11 ports 46000-46999 3 ports 47000-47999 8 ports 48000-48999 14 ports 49000-49999 3 ports 51000-51999 1 port
Port ranges, and what a port number really tells you
Registered: 1024 to 49151
Assigned by IANA to applications on request: databases, VPNs, games, vendor software.
Dynamic: 49152 to 65535
Never assigned. The operating system picks them as the source port of outgoing connections.
A registry says what a port is assigned to, not what runs on a host. Any program can listen on any port. Each port page lists the commands that show the real process on Linux, macOS and Windows.
Free port lookup API
JSON, no key, cross-origin requests allowed. Please cache responses. Data under CC BY 4.0: credit CyberHunter with a link.
One port, by number or service name
curl https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports/3389 curl https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports/ssh
Search and filters
curl "https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports/search?q=remote+desktop" curl "https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports?category=databases&risk=high,critical&sort=-risk" curl "https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports?min=8000&max=8100&protocol=tcp&limit=100"
Export and metadata
curl -o ports.csv "https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports?format=csv" curl https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports/categories curl https://cyberhunter-preprod.apps.bastiencordier.pro/api/ports/stats
List parameters: q, protocol, category, range (well-known, registered,
dynamic), risk (low, moderate, high, critical), encrypted (yes, no, optional), min,
max, curated, sort (popularity, port, -port, -risk, name), limit (1-100) and
offset. Comma-separated values are combined.
What is a port number?
A port is a 16-bit number (0 to 65535) that tells a computer which program should receive a network connection. The IP address finds the machine, the port finds the service on it: web servers listen on 443, SSH on 22, Remote Desktop on 3389.
What are well-known, registered and dynamic ports?
IANA splits the range in three. Well-known ports (0-1023) are assigned to core services and usually need administrator rights to open. Registered ports (1024-49151) are assigned to applications on request. Dynamic or ephemeral ports (49152-65535) are never assigned: operating systems use them for the client side of connections.
What is the difference between TCP and UDP ports?
TCP and UDP have separate port spaces, so TCP 53 and UDP 53 are two different endpoints. TCP is connection-based and reliable (web, SSH, databases); UDP is connectionless and faster (DNS queries, VoIP, games, QUIC). Many services are registered on both even if they use only one.
Does a port number tell me which program is running?
No. The registry says what a port is assigned to, not what actually listens on a given host. Any program can use any port, and attackers often hide services on common ones. Use the commands on each port page (ss, lsof, netstat) to see the real process.
Which ports are dangerous to leave open?
The riskiest ones to expose on the Internet are remote administration (RDP 3389, VNC 5900, Telnet 23), file sharing (SMB 445), databases (Redis 6379, MongoDB 27017, Elasticsearch 9200, MySQL 3306), container APIs (Docker 2375, kubelet 10250) and industrial protocols (Modbus 502). Filter the list by risk to see them all.
Is there an API?
Yes. /api/ports lists and filters ports, /api/ports/{port} returns one port by number or service name, /api/ports/search ranks matches, and /api/ports/categories and /api/ports/stats describe the dataset. It is free, needs no key and allows cross-origin requests. Add format=csv to export a list.