Are there any firewalls that interfere with SMTP Authentication?

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SMTP Authentication can be a stumbling block on the road to secure mail transmission. This article describes the most common SMTP authentication firewall problems and their solutions.

Yes. Some types of firewalls will interfere with SMTP Authentication, preventing you from being able to send mail.

  • Disable scanning of SMTP traffic on their firewall.
  • Use their ISP’s SMTP server to send outbound mail since most ISP’s can authenticate based upon IP address rather than username/password.

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