Mos's blog: How to Proxy SSL IMAP/POP3/SMTP using HAProxy and Dovecot+Postfix
How to Setup Nginx as Mail Proxy on Ubuntu Server
How to Configure an SMTP Relay Connector in Exchange Server 2013
How to Configure Mail Proxy Settings in Office Outlook for Free Mail?
GitHub - emersion/go-smtp-proxy: A go-smtp-server backend that proxies messages to another SMTP server
Proxy Server using Nginx
How to Configure Your Barracuda Message Archiver to Act as an SMTP Proxy to Your Email Server | Barracuda Campus
MailStore Proxy - MailStore Server Help
Combat SPAM with Anti-Spam SMTP Proxy (ASSP) - MajorGeeks
MailStore Proxy - MailStore Server Help
SMTP proxy server
Anti-Spam SMTP Proxy Server / Wiki / ASSP_Advanced_Workflow
SMTP proxy | Semantic Scholar
What is a Proxy Server? A Clear Explanation of How it Works | UpGuard
Using the SMTP Proxy to Protect your E-mail Server
Setting up SMTP proxy for email client
How to configure the email proxy for both inbound and outbound spam and virus filtering on Panda GateDefender eSeries - Technical Support - Panda Security
How To Install CleanMail As SMTP Proxy On Your Mail Server
Mail infrastructure with dovecot proxy - Server Fault
Using the SMTP Proxy to Protect your E-mail Server
Mail Proxy - Basic Setup – Endian
SMTP-Proxy: Mail From/Rcpt To
Set Up SMTP and IMAP Proxy with HAProxy (Debian, Ubuntu, CentOS)
SMTP-Proxy: General Settings
Putting It All Together (Building Internet Firewalls, 2nd Edition)
