Disable VRFY and EXPN SMTP Commands for Improved Security

[maneeshaxyz]

Description:

Currently, we respond to the VRFY and EXPN SMTP commands, which can be exploited to:

• Enumerate valid email addresses or system usernames (VRFY)

• Reveal internal mailing list members (EXPN)

These commands are considered legacy and unnecessary for normal email operations.

Requirement

Disable VRFY and EXPN in the SMTP configuration by default

Expected Behavior:

• No disruption to normal mail sending/receiving

• Improved server hardening

• Reduced attack surface