Free port number lookup. Search well-known TCP and UDP ports by number or service name with protocol, description and risk flags from a bundled IANA-based dataset. Fully offline, no network requests.
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What is Port Number Lookup?
The Port Number Lookup identifies what a TCP or UDP port is for, from a bundled dataset of 60+ well-known and commonly deployed services based on the IANA registry. Search by number or service name, filter by protocol, and read plain-language descriptions plus risk flags that explain why ports like SMB, RDP, Redis and Elasticsearch keep appearing in security reports — all computed locally with no network requests.
Key Benefits
Instant identification of unknown ports in scan and netstat reports
Risk flags with reasons, not just colours
Protocol filtering across TCP, UDP and dual-stack services
Works completely offline: the dataset ships with the page
One consistent reference for mixed Windows, Linux and cloud teams
Common Use Cases
•Investigating an unfamiliar listener found in a netstat output
•Reviewing firewall rules before opening ports for a new service
•Checking which database port a vendor tool connects to
•Training new admins on which ports are dangerous to expose
•Verifying that a hardening checklist covers the usual suspects
How to Look Up a Network Port
Search by number or name: Type a port number like 3389 or a service name like ssh. Matching is instant against the bundled dataset.
Filter by protocol: Switch between TCP, UDP and all protocols to narrow the list to the transport you care about.
Read the risk flag: High-risk ports include a note explaining why they are abused, from cleartext credentials to unauthenticated databases, so you can decide whether the port should be reachable.
Key Features
60+ well-known and commonly deployed ports in a bundled dataset
Search by port number prefix or by service name substring
TCP, UDP or all-protocol filtering
Low, medium and high risk flags with plain-language reasons
Elasticsearch REST API.Unauthenticated instances leak and wipe whole datasets.
High
11211
TCP/UDP
memcached
Memcached memory cache.Amplified into record DDoS floods when exposed (memcrashed).
High
27017
TCP
mongod
MongoDB database.Unauthenticated instances were mass-wiped by Meow attacks.
High
50000
TCP
db2
IBM Db2 database listener.
Medium
About this lookup
This port number lookup answers what a TCP or UDP port is used for, straight from a bundled dataset based on the IANA service name registry plus the services most commonly found in real deployments. Search by number or by service name, filter by protocol, and read plain-language descriptions of what each port carries. Frequently abused ports carry a risk flag with the reason: cleartext credentials, ransomware entry points, unauthenticated databases and the like. The dataset is embedded in the page, so lookups work completely offline.
Why use it
Identify unknown listeners in a netstat or scan report by number or name.
Check which ports a firewall rule should allow before opening anything.
See risk notes that explain why a port keeps appearing in security reports.
Compare TCP and UDP services without leaving the page or searching online.
Work air-gapped: the whole dataset ships with the page, no API calls.
Features
60+ well-known and commonly deployed ports in a bundled dataset
Search by port number prefix or by service name substring
TCP, UDP or all-protocol filtering
Low, medium and high risk flags with plain-language reasons