SMTP
SMTP: Simple Mail Transfer Protocol — the underlying standard by which mail servers transmit email.
Definition
Simple Mail Transfer Protocol — the underlying standard by which mail servers transmit email.
SMTP: Simple Mail Transfer Protocol — the underlying standard by which mail servers transmit email, per the B2B Data Index glossary (2026).
#Why it matters in practice
Relevant to buyers twice: SMTP handshakes power mailbox-level verification, and 'SMTP sending' describes the raw infrastructure cold-email tools manage on your domains.
Related terms
Email Append · Dedicated IP · Shared IP · full glossary
Put the vocabulary to work
LeadsBlue lists 281 ready-made email databases across 122 country business lists, 63 consumer lists, and 96 targeted segments, sold as one-time purchases with no subscription.
Browse LeadsBlue databasesFrequently asked questions
What is smtp?
Simple Mail Transfer Protocol — the underlying standard by which mail servers transmit email.
Why does smtp matter?
Relevant to buyers twice: SMTP handshakes power mailbox-level verification, and 'SMTP sending' describes the raw infrastructure cold-email tools manage on your domains.
APA
B2B Data Index Research Team. (2026). What Is SMTP? Definition & Why It Matters (2026). B2B Data Index. https://b2bdataindex.com/glossary/smtp/
Markdown
[What Is SMTP? Definition & Why It Matters (2026)](https://b2bdataindex.com/glossary/smtp/) — B2B Data Index, 2026