Software

GNU 68HC1x

Xcra

Ada

Sysadmin

Hardware

LPS

EBCS

PCS

Z80

PPEP

Design

Tektronic 468

SMTP

• RFC5321: Simple Mail Transfer Protocol
• RFC5322: Internet Message Format
• RFC6409: Message Submission for Mail
• RFC5983: Mailing Lists and Internationalized Email Addresses
• RFC6530: Overview and Framework for Internationalized Email
• RFC8314: Cleartext Considered Obsolete: Use of Transport Layer Security (TLS) for Email Submission and Access

RSPAMD

• rspamd

Problems & Solutions

SPF issues

• EHLO miss-match between announced name, IP and reverse
• missing TXT SPF record for the announced EHLO name

Example: if MX is smtp.vacs.fr

• reverse DNS of server IP must be smtp.vacs.fr
• there must be a TXT record 'smtp.vacs.fr' with v=spf1 a mx -all

verify with https://www.mail-tester.com

See SPF Common Mistakes