Pronunciation: [hˈiːlə͡ʊ] (IPA) 
The proper spelling of the word "HELO" is actually incorrect. The correct spelling should be "HELLO". The phonetic transcription in the International Phonetic Alphabet (IPA) for "HELLO" would be /hɛˈloʊ/. This consists of the consonant sound /h/ followed by the diphthong /ɛˈ/ and the vowel sound /oʊ/. It is important to use correct spelling in written communication to ensure clarity and credibility.
HELO, short for "Hello," is a computer networking command used in the context of Simple Mail Transfer Protocol (SMTP) to initiate a connection between email servers and exchange information. It is sent by the client SMTP server to the receiving server as a form of introduction and to establish a communication channel.
In the SMTP protocol, when a client server connects to a remote server to deliver email messages, it first sends the HELO command followed by the domain name of the sending server. For example, "HELO example.com." This command serves to identify the sending server and initiate the SMTP session.
The recipient server then responds with a code 250 status if the HELO command is accepted. This allows the client and server to exchange information about their capabilities, such as supported extensions, protocols, and configuration options. The information shared during the HELO command helps in the negotiation and handling of the email transaction between the servers.
HELO is an essential step in the SMTP handshake process and establishes the initial link between the sender and receiver. It represents the initial greeting and essentially asks for permission to send email to the receiving server. By exchanging HELO commands, email servers ensure proper communication and facilitate the transmission of messages across the internet.
