Available Protocols to Configure a Cloud Load Balancer

The following list provides information about the protocols you can choose when configuring a Cloud Load Balancer:

  • DNS (TCP) - Works with IPv6 and allows your DNS server to receive traffic using TCP port 53.

  • DNS (UDP) - Works with IPv6 and allows your DNS server to receive traffic using UDP port 53.

  • FTP - The File Transfer Protocol defines how files are transported over the internet using port 21 and its data transfer can use TCP port 20. It's typically used when downloading or uploading files to or from web servers.

  • HTTP - The Hypertext Transfer Protocol defines how communications occur on the internet between clients and web servers using port 80. For example, if you request a web page in your browser, HTTP defines how the web server fetches the page and returns it your browser.

  • HTTPS - The Hypertext Transfer Protocol over Secure Socket Layer (SSL) provides encrypted communication over the internet using port 443. It securely verifies the authenticity of the web server you're communicating with.

  • IMAPS - The Internet Message Application Protocol over Secure Socket Layer (SSL) defines how an email client, such as Microsoft Outlook, retrieves and transfers email messages with a mail server using port 993.

    • IMAPv2 - Version 2 of IMAPS.
    • IMAPv3 - Version 3 of IMAPS.
    • IMAPv4 - Version 4, and the current version of IMAP.
  • LDAP - The Lightweight Directory Access Protocol provides access to distributed directory information services over the Internet using port 389. This protocol is typically used to access a large set of hierarchical
    records, such as corporate email or a telephone directory.

  • LDAPS - The Lightweight Directory Access Protocol over Secure Socket Layer (SSL) using port 636. See LDAP above.

  • MYSQL - This protocol allows communication with MySQL, an open source database management system using 3306.

  • POP3 - The Post Office Protocol is one of the two most common protocols for communication between email clients and email servers. Version 3 is the current standard of POP using port 110.

  • POP3S - Post Office Protocol over Secure Socket Layer. See POP3 above using port 995.

  • SFTP - The SSH File Transfer Protocol is a secure file transfer and management protocol using port 22. This protocol assumes the files are using a secure channel, such as SSH, and that the identity of the client is available
    to the protocol.

  • SMTP - The Simple Mail Transfer Protocol is used by electronic mail servers to send and receive email messages using port 25. Email clients use this protocol to relay messages to another computer or web server, but use IMAP or POP to send and receive messages.

  • TCP - The Transmission Control Protocol is a part of the Transport Layer protocol and is one of the core protocols of the Internet Protocol Suite. It provides a reliable, ordered delivery of a stream of bytes from one program on a computer to another program on another computer. Applications that require an ordered and reliable delivery of packets use this protocol. See UDP.

  • TCP (Client First) - This protocol is similar to TCP, but is more efficient when a client is required to write the data to the server before receiving the server's response.

    Note: TCP_CLIENT_FIRST cannot be placed on a VIP that already dispatches HTTP.

  • TCP (Stream) - TCP Streaming allows either the client or server to send the first message when a connection is established. This option is for protocols where there is no request-response semantic. Either side of the connection can write the first message, with no response being necessarily required or expected.

  • UDP - The User Datagram Protocol provides a datagram service that emphasizes speed over reliability, It works well with applications that provide security through other measures.

  • UDP (Stream) - This protocol is designed to stream media over networks and is built on top of UDP.

Limitations for UDP Protocols

UDP-Based protocols (DNS over UDP, UDP, and streaming UDP) are not capable of using the Health Monitor features. Also, SSL Termination is unavailable when using UDP-based ports.