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Port Lookup

Search by port number, service name or a word such as “database” or “plaintext”, then open the entry for transport, encryption and exposure notes.

Search by number, service or risk

The search matches the port number, the service name, the summary and the facts in each entry. A query such as database returns the database ports, while plaintext returns the services that send credentials without encryption. The group filter narrows the list to web, mail, remote access, infrastructure or database services.

The full dataset is present in the page as text and links, so the directory is usable and crawlable without JavaScript. The script only hides rows that do not match.

What each entry states

Every entry lists the transport, the service, whether encryption is part of the protocol, and the exposure risk. The practical sections explain why the port exists and what happens when it faces the public internet. The facts come from the IANA service registry and the relevant protocol specifications.

A port being open is not proof of a vulnerable service, and a closed port is not proof of safety. Use the reference to understand what should be there, then verify with your own inventory and firewall rules.

All 20 ports, searchable

Every entry links to its full reference page. The search box above filters this list.

port-2020 — FTP data Port 20 carries FTP data in active mode, from server to client. port-2121 — FTP control Port 21 carries FTP commands and responses, including credentials in plain FTP. port-2222 — SSH Port 22 carries SSH: encrypted remote shell, SFTP, SCP and port forwarding. port-2323 — Telnet Port 23 is the legacy Telnet service, which sends everything including passwords in clear text. port-2525 — SMTP Port 25 is the classic SMTP port for server-to-server mail delivery. port-5353 — DNS Port 53 resolves domain names, over UDP for queries and TCP for large answers or zone transfers. port-8080 — HTTP Port 80 is the default port for plain HTTP. port-110110 — POP3 Port 110 is the POP3 mailbox protocol, traditionally download-and-delete. port-143143 — IMAP Port 143 is IMAP, which keeps mail on the server and synchronises folders across devices. port-443443 — HTTPS Port 443 is the default port for HTTPS and for HTTP/3 over QUIC. port-445445 — SMB Port 445 carries SMB file sharing on Windows networks and must never face the internet. port-587587 — SMTP submission Port 587 is the authenticated submission port for sending mail from a client. port-993993 — IMAPS Port 993 is IMAP over TLS, encrypted from the first byte. port-995995 — POP3S Port 995 is POP3 over TLS, encrypted from the first byte. port-33063306 — MySQL Port 3306 is the default MySQL and MariaDB listener. port-33893389 — RDP Port 3389 is Microsoft Remote Desktop, a frequent target for brute force and ransomware. port-54325432 — PostgreSQL Port 5432 is the default PostgreSQL listener. port-63796379 — Redis Port 6379 is the default Redis listener, and an unauthenticated Redis is a common breach. port-80808080 — HTTP alternate Port 8080 is a common alternate HTTP port for proxies, development servers and admin panels. port-84438443 — HTTPS alternate Port 8443 is a common alternate HTTPS port for admin interfaces and application servers. port-2701727017 — MongoDB Port 27017 is the default MongoDB listener and a repeated target of mass ransom campaigns.

Frequently asked questions

Does the lookup scan my host?

No. It searches a static reference list in the page. It makes no network requests.

Why are only 20 ports listed?

The set covers the ports most often met in web, mail, remote-access and database work. Vendor-specific ports are out of scope.

Is a non-default port safer?

It may reduce automated noise, but it is not a security control. Binding, authentication and firewall rules are.

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Reference

20 — FTP dataPort 20 carries FTP data in active mode, from server to client. 21 — FTP controlPort 21 carries FTP commands and responses, including credentials in plain FTP. 22 — SSHPort 22 carries SSH: encrypted remote shell, SFTP, SCP and port forwarding. 23 — TelnetPort 23 is the legacy Telnet service, which sends everything including passwords in clear text. 25 — SMTPPort 25 is the classic SMTP port for server-to-server mail delivery. 53 — DNSPort 53 resolves domain names, over UDP for queries and TCP for large answers or zone transfers.

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