Common Port Lookup
Look up common ports like 22, 53, 80, 443, 3389, 5432, and more.
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Use the example or enter your own subnet, plan, MAC, or port value.
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Look up common TCP/UDP ports and see whether a port is well-known, registered, or dynamic/private.
Common port lookup details
Search common ports, compare TCP/UDP nuance, and copy a starter firewall-rule snippet.
Encrypted web traffic over TLS.
Keep TLS current, redirect HTTP, and limit admin paths by source or authentication.
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| Port | Protocol | Service | Description | Related / nuance |
|---|---|---|---|---|
| 20 | TCP | FTP data | File Transfer Protocol data channel. | 21/TCP control |
| 21 | TCP | FTP control | File Transfer Protocol command channel. | 20/TCP data, passive FTP high ports |
| 22 | TCP | SSH | Secure Shell remote login and tunneling. | SFTP also uses 22/TCP |
| 23 | TCP | Telnet | Legacy unencrypted remote terminal service. | 22/TCP SSH |
| 25 | TCP | SMTP | Email transfer between mail servers. | 465/TCP SMTPS, 587/TCP submission |
| 53 | TCP | DNS | DNS zone transfers and larger DNS responses. | 53/UDP common queries |
| 53 | UDP | DNS | Common DNS queries. | 53/TCP fallback/zone transfers |
| 67 | UDP | DHCP server | DHCP server messages. | 68/UDP client |
| 68 | UDP | DHCP client | DHCP client messages. | 67/UDP server |
| 80 | TCP | HTTP | Unencrypted web traffic. | 443/TCP HTTPS, 8080/TCP alternate |
| 110 | TCP | POP3 | Email retrieval. | 995/TCP POP3S |
| 123 | UDP | NTP | Network Time Protocol. | NTS often uses 4460/TCP |
| 143 | TCP | IMAP | Email retrieval and mailbox sync. | 993/TCP IMAPS |
| 161 | UDP | SNMP | Network monitoring and management. | 162/UDP traps |
| 389 | TCP | LDAP | Directory services. | 636/TCP LDAPS |
| 443 | TCP | HTTPS | Encrypted web traffic over TLS. | 80/TCP HTTP, 8443/TCP alternate HTTPS |
| 445 | TCP | SMB | Windows file sharing and domain services. | 139/TCP NetBIOS session service |
| 465 | TCP | SMTPS | SMTP over TLS. | 25/TCP SMTP, 587/TCP submission |
| 500 | UDP | IKE | IPsec VPN key exchange. | 4500/UDP NAT-T, ESP protocol 50 |
| 587 | TCP | SMTP submission | Authenticated email submission. | 25/TCP SMTP, 465/TCP SMTPS |
| 636 | TCP | LDAPS | LDAP over TLS. | 389/TCP LDAP |
| 993 | TCP | IMAPS | IMAP over TLS. | 143/TCP IMAP |
| 995 | TCP | POP3S | POP3 over TLS. | 110/TCP POP3 |
| 1433 | TCP | Microsoft SQL Server | SQL Server database connections. | 1434/UDP SQL Browser |
| 1521 | TCP | Oracle Database | Oracle listener default port. | 2484/TCP TCPS common alternative |
| 3306 | TCP | MySQL/MariaDB | MySQL and MariaDB database connections. | 33060/TCP MySQL X Protocol |
| 3389 | TCP | RDP | Microsoft Remote Desktop Protocol. | 3391/UDP RD Gateway transport |
| 4500 | UDP | IPsec NAT-T | IPsec VPN NAT traversal. | 500/UDP IKE, ESP protocol 50 |
| 5432 | TCP | PostgreSQL | PostgreSQL database connections. | 6432/TCP PgBouncer common alternative |
| 5900 | TCP | VNC | Virtual Network Computing remote desktop. | 5800/TCP browser-based VNC variants |
| 6379 | TCP | Redis | Redis database/cache default port. | 6380/TCP TLS/common managed Redis |
| 8080 | TCP | HTTP alternate | Common alternate web or proxy port. | 80/TCP HTTP, 8443/TCP HTTPS alternate |
| 8443 | TCP | HTTPS alternate | Common alternate TLS web/admin port. | 443/TCP HTTPS, 8080/TCP HTTP alternate |
Firewall rule notes
- Replace
<destination>and source scope before implementation; “any” is only a placeholder. - Confirm whether the application actually uses TCP, UDP, or both.
- Prefer allowlists, private networking, VPN, and service-specific authentication over broad exposure.
Notes
These are planning and conversion utilities. Confirm production network changes against your router, firewall, cloud provider, and ISP requirements before applying them.
Get a better answer from the Common Port Lookup
- Start with the example values to see how the tool behaves.
- Swap in your own numbers, even if they are rough first-pass estimates.
- Change one input at a time so you can see what actually moves the result.
What the result means
The result turns network notation into something easier to read: ranges, host counts, masks, wildcard masks, ports, or planning blocks.
How to use it
Use the output to plan or double-check, then compare it with the real network before changing a route, VLAN, DHCP scope, firewall rule, or ACL.
What can change it
A valid network number can still be wrong for your environment if it overlaps, conflicts with routing, exposes traffic, or breaks change-control rules.
Example to try
Look up the service, then copy the firewall snippet only after replacing placeholders and narrowing the source scope.
Assumption to challenge
Common ports are conventions, not proof. Applications can use custom ports, multiple protocols, dynamic ranges, or TLS termination elsewhere.
Verify next
Confirm TCP/UDP, source and destination, authentication, exposure risk, logging, monitoring, and rollback before opening access.
Common uses
- Identify common service ports.
- Check TCP vs UDP defaults.
- Document firewall rules.
Common questions
Is the Common Port Lookup private?
Yes. CalcShelf calculators run without an account, do not save calculator entries, and do not put raw inputs into shareable URLs or analytics events.
How accurate is the Common Port Lookup?
It follows common IPv4, CIDR, mask, range, and port conventions. Production networks still need live-config, routing, ACL, overlap, and change-control review.
What should I check after using the Common Port Lookup?
Verify live allocations, overlaps, gateway conventions, routes, ACL/firewall order, documentation, and rollback plan before production changes.
Which calculator should I try next?
Use the related calculators below to cross-check the same decision from another angle before you act.
Method behind the estimate
Networking tools use IPv4, CIDR, subnet mask, wildcard mask, range, VLAN, DHCP, and port-reference rules for planning and sanity checks.
Why the detail matters
Before changing production routing, firewall, VLAN, DHCP, or address plans, verify against the actual network, documentation, and change-control process.
Privacy guardrail
Your calculator values are for you. CalcShelf does not require an account, save calculator entries, put your numbers into shareable URLs, or use raw inputs as analytics events.
Copy or print safely
Use any copy, print, or worksheet controls as local handoff tools for your own notes, supplier calls, lender questions, or implementation checklist. They are there to help you explain the result to a human.
Before acting
Treat the result as a decision draft, not a verdict. Recheck the source numbers, run a downside case, and verify the real-world rule, quote, label, or spec that controls the final answer.
Last reviewed: May 11, 2026. See methodology and editorial policy for formulas, assumptions, rounding, review approach, and limitations. For network changes, verify against live configuration, vendor docs, and change-control requirements.