Port Reference Guide

Interactive reference for common network ports used by system administrators and security architects. Search by port number or service, filter by protocol and category, with security notes.

82 ports found

PortProtocolServiceSecurity
80TCPHTTPInsecure
443TCPHTTPSSafe
8080TCPHTTP AltCaution
8443TCPHTTPS AltSafe
25TCPSMTPInsecure
465TCPSMTPSSafe
587TCPSMTP SubmissionSafe
110TCPPOP3Insecure
995TCPPOP3SSafe
143TCPIMAPInsecure
993TCPIMAPSSafe
20TCPFTP DataInsecure
21TCPFTP ControlInsecure
22TCPSFTP/SSHSafe
69UDPTFTPInsecure
989TCPFTPS DataSafe
990TCPFTPS ControlSafe
22TCPSSHSafe
23TCPTelnetInsecure
3389TCPRDPCaution
5900TCPVNCCaution
53TCP/UDPDNSCaution
67UDPDHCP ServerCaution
68UDPDHCP ClientCaution
123UDPNTPCaution
161UDPSNMPCaution
162UDPSNMP TrapCaution
853TCPDNS over TLSSafe
3306TCPMySQLCaution
5432TCPPostgreSQLCaution
1433TCPMSSQLCaution
1521TCPOracle DBCaution
27017TCPMongoDBCaution
6379TCPRedisCaution
9200TCPElasticsearchCaution
5984TCPCouchDBCaution
9042TCPCassandraCaution
11211TCPMemcachedCaution
500UDPIKESafe
1194TCP/UDPOpenVPNSafe
1723TCPPPTPInsecure
4500UDPIPSec NAT-TSafe
51820UDPWireGuardSafe
5222TCPXMPP ClientCaution
5269TCPXMPP ServerCaution
6667TCPIRCInsecure
6697TCPIRC TLSSafe
1883TCPMQTTCaution
8883TCPMQTT TLSSafe
5672TCPAMQPCaution
5671TCPAMQP TLSSafe
3000TCPDev ServerCaution
4200TCPAngular CLICaution
5173TCPViteCaution
8000TCPPython/PHP DevCaution
9090TCPPrometheusCaution
3100TCPGrafana LokiCaution
2375TCPDocker (unenc)Insecure
2376TCPDocker TLSSafe
6443TCPKubernetes APISafe
10250TCPKubeletCaution
2379TCPetcd ClientCaution
2380TCPetcd PeerCaution
8500TCPConsulCaution
554TCPRTSPCaution
1935TCPRTMPCaution
8554TCPRTSP AltCaution
3128TCPSquid ProxyCaution
8081TCPHTTP ProxyCaution
9443TCPHTTPS ProxySafe
514UDPSyslogCaution
6514TCPSyslog TLSSafe
9100TCPNode ExporterCaution
3000TCPGrafanaCaution
5601TCPKibanaCaution
8080TCPJenkinsCaution
9000TCPSonarQubeCaution
8200TCPVaultSafe
9092TCPKafkaCaution
4369TCPEPMDCaution
15672TCPRabbitMQ MgmtCaution
4222TCPNATSCaution

How to Use the Port Reference Guide

  1. 1

    Search by Port Number or Service Name

    Type a port number like 443 or a service name like SSH into the search bar. The guide instantly filters results to show matching entries with protocol details, descriptions, and security ratings.
  2. 2

    Filter by Protocol or Category

    Use the Protocol dropdown to narrow results to TCP-only or UDP-only ports. Select a Category filter to focus on a specific group such as Web, Database, Email, or File Transfer services.
  3. 3

    Review Security Ratings and Notes

    Each port entry includes a security badge: Safe (encrypted or inherently secure), Caution (secure with proper configuration), or Insecure (plaintext or vulnerable by default). Click any entry to expand its detailed security notes and recommended alternatives.
  4. 4

    Apply Findings to Your Firewall Rules

    Use the security information to build or audit your firewall configuration. Block insecure ports you do not need, allow only required services, and replace legacy protocols with their encrypted counterparts identified in the guide.

Common Use Cases

1

Firewall Configuration and Auditing

System administrators use this reference when writing or reviewing firewall rules. Quickly confirm which port a service needs, check whether the protocol is encrypted, and decide whether to allow, restrict, or block the traffic.
2

Penetration Testing and Security Assessments

Security professionals reference port assignments during network scans and vulnerability assessments. The security ratings help prioritize which open ports represent the highest risk and need immediate remediation.
3

Troubleshooting Network Connectivity

When a service fails to connect, engineers look up the expected port and protocol to verify that firewalls, load balancers, and security groups are configured correctly. The guide eliminates guesswork by providing definitive port-to-service mappings.
4

Cloud Infrastructure and Container Security

DevOps teams building AWS security groups, Azure NSGs, or Kubernetes network policies use this reference to define precise ingress and egress rules. Knowing the exact ports for services like PostgreSQL (5432), Redis (6379), or Elasticsearch (9200) prevents overly permissive configurations.

Why Use Port Reference Guide?

Understanding network ports is essential for system architects designing secure infrastructure, firewall administrators writing access control rules, and security teams performing penetration tests or incident response. This interactive reference covers the most commonly used TCP and UDP ports with security ratings and detailed notes. Use it to quickly identify what services run on specific ports, assess their security implications, and make informed decisions about which ports to open or block in your firewall configurations.

The Port Reference Guide is a searchable, filterable database of common TCP and UDP network ports used across modern infrastructure. It covers well-known ports (0-1023) assigned by IANA, registered ports used by popular applications and databases, and service ports for protocols ranging from HTTP and SSH to MQTT and gRPC. Each entry includes the port number, protocol type, service name, a plain-language description, and a security rating that flags whether the default protocol is safe, requires caution, or is inherently insecure.

This tool is designed for system administrators writing firewall rules, security engineers running assessments, and DevOps teams configuring cloud security groups. Instead of searching through scattered documentation or memorizing port numbers, you get a single interactive reference with instant search and filtering. Combine it with the DNS Lookup tool to verify that domain names resolve to the correct IPs behind your firewall rules, or run the Security Headers Analyzer after opening web-facing ports to confirm your HTTP security headers are properly configured.

For deeper network analysis, use the Subnet Calculator to plan IP address ranges alongside your port configurations, check domain ownership with WHOIS Lookup, or verify SSL certificates on HTTPS ports using the SSL Certificate Checker. Everything runs in your browser with no data uploaded to external servers, making it safe to reference even when working with sensitive infrastructure details.

How It Compares

Traditional port references like the IANA Service Name and Transport Protocol Port Number Registry provide authoritative data but offer no filtering, no search, and no security context. Wikipedia port lists are comprehensive but lack interactivity and security ratings. Command-line tools like grep /etc/services or getent services work offline but show only port-to-service mappings without descriptions or security guidance.

The FindUtils Port Reference Guide combines the accuracy of official registries with interactive search, protocol and category filters, and color-coded security ratings. Unlike static reference pages, you can instantly narrow results to find exactly the port you need. The security notes provide actionable guidance on whether a port's default protocol is safe or should be replaced with an encrypted alternative. All processing is client-side, so it works on any device without installation, and you can use it freely without creating an account or paying for a subscription.

Tips for Network Port Security

1
Always replace insecure protocols with encrypted alternatives: use SSH (22) instead of Telnet (23), SFTP (22) instead of FTP (21), and HTTPS (443) instead of HTTP (80).
2
Apply the principle of least privilege to firewall rules. Only open the specific ports your services require, and restrict source IP ranges whenever possible.
3
Use port knocking or VPN access for sensitive management ports like SSH (22) and RDP (3389) to reduce exposure to brute-force attacks.
4
Run regular port scans on your own infrastructure with tools like nmap to detect unintended open ports or services that should have been decommissioned.
5
Document every open port in your infrastructure with a justification. Unexplained open ports are a common finding in security audits and penetration tests.

Frequently Asked Questions

1

What is a network port?

A network port is a virtual endpoint for communication. It's a 16-bit number (0-65535) that identifies a specific process or service on a device. When combined with an IP address, a port creates a unique socket for network communication. For example, web servers typically listen on port 443 (HTTPS).
2

What is the difference between TCP and UDP?

TCP (Transmission Control Protocol) provides reliable, ordered delivery with error checking and flow control. It's used for web browsing, email, and file transfers. UDP (User Datagram Protocol) is faster but unreliable — it doesn't guarantee delivery or order. It's used for DNS queries, video streaming, and gaming.
3

Which ports should I block in my firewall?

Block all ports that aren't needed for your services. Common ports to block include: 23 (Telnet - unencrypted), 21 (FTP - unencrypted), 135-139 (NetBIOS), 445 (SMB), and 1433/3306 (databases) from external access. Always use the principle of least privilege — only open ports that are absolutely necessary.
4

What are well-known ports?

Well-known ports (0-1023) are assigned by IANA for common services. Registered ports (1024-49151) are for vendor applications. Dynamic/private ports (49152-65535) are used for temporary connections. On Unix/Linux systems, binding to well-known ports requires root privileges.
5

How do I check which ports are open on my server?

Use `netstat -tlnp` or `ss -tlnp` on Linux to see listening ports. On Windows, use `netstat -an`. For external scanning, tools like nmap can probe a host's open ports. Always ensure you have authorization before scanning — unauthorized port scanning may violate security policies or laws.

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