Definition
TLS certificates secure the connections that carry email between servers, enabling encrypted transport and proving server identity.
Keeping certificates valid and protocols strong protects mail in transit.
TLS certificates secure mail in transit and protect against downgrade attacks, making them a security baseline. Keeping them valid and protocols current prevents failures. Monitoring expiry prevents silent downtime.
Managing TLS
Keep certificates valid and renewed before expiry.
Pin to strong CAs and current protocols.
Why It Matters
TLS certificates secure mail in transit and protect against downgrade attacks. Understanding them keeps your infrastructure safe.
Best Practices
- Keep certificates valid and renewed before expiry.
- Pin to strong CAs and current protocols.
- Watch for downgrade attempts on transport.
- Monitor certificate expiry alerts.
- Use current TLS versions.
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Related Glossary Terms
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Email Authentication Protocols
Email authentication protocols are technical standards that verify the identity of an email sender, helping mailbox providers distinguish legitimate mail from spam and phishing.
BIMI
BIMI (Brand Indicators for Message Identification) is an email standard that allows brands to display their logo next to their emails in supported email clients. It requires DMARC enforcement at quarantine or reject policy.
Bounce Classification
Bounce classification uses SMTP codes (550, 551, 552, 553, 554, 450, 451, 452) and enhanced status codes to categorise permanent and transient delivery failures.
Email Deliverability
Email deliverability is the ability to land in the recipient's inbox rather than the spam folder. It depends on sender reputation, authentication, list quality, and content practices.
DKIM (DomainKeys Identified Mail)
DKIM (DomainKeys Identified Mail) is an email authentication method that uses digital signatures to verify that an email was not tampered with during transit and comes from a authorised domain.
Frequently Asked Questions
To encrypt SMTP transport and prove server identity. TLS certificates secure mail in transit and protect against downgrade attacks, making them a security baseline.
Yes, but insecure; modern servers prefer TLS. Keeping them valid and protocols current prevents failures.
TLS used if both sides agree, not enforced. Monitoring expiry prevents silent downtime.
Connections fail or downgrade. TLS certificates secure mail in transit and protect against downgrade attacks, making them a security baseline.
Use expiry alerts and monitoring tools. Keeping them valid and protocols current prevents failures.