Questions and answers

How do I disable Vrfy?

How do I disable Vrfy?

To disable VRFY on IMSVA:

  1. Log in to your IMSVA box using root.
  2. Go to /opt/trend/imss/postfix/etc/postfix directory.
  3. Edit the file.
  4. Add the following line at the bottom of the file then save the changes:
  5. Reload postfix using the following command:
  6. Verify if configuration is active using the following command:

How do I disable VRFY and EXPN on my mailserver?

Solution: Disable VRFY and/or EXPN on your Mailserver. For postfix add ‘disable_vrfy_command=yes’ in ‘’. For Sendmail add the option ‘O PrivacyOptions=goaway’.

What is VRFY command?

The VRFY command enables SMTP clients to send a request to an SMTP server to verify that mail for a specific user name resides on the server. The VRFY command is defined in RFC 821. The server sends a response indicating whether the user is local or not, whether mail will be forwarded, and so on.

What is TXT Vrfy?

Hi, VRFY command is used to verify a user ID on a mail domain. It can be used to test for valid user IDs. Disabling the command helps prevent “spoofing” by not allowing someone outside your network to check if a user ID is valid.

How do you harden postfix?

Postfix Hardening Guide for Security and Privacy

  1. Basic hardening. Disable VRFY (verify)
  2. Prevent unwanted email relaying. Networks.
  3. Incoming email configuration. Enable HELO.
  4. Outgoing email configuration. Configure authenticated relaying with a smarthost.
  5. Cryptography, encryption, and privacy. Enable TLS logging.

What is Rcpt to command?

The RCPT TO command specifies the recipient. As an argument, RCPT TO includes a destination mailbox (forward-path). In case of multiple recipients, RCPT TO will be used to specify each recipient separately.

What is SMTP crack?

SMTP cracking / SMTP checking process The SMTP cracker / SMTP checker reads the next combo from the list loaded before. It looks up the e-mail domain in the “smtphost” dictionary for the SMTP-host to attack. For unknown hosts, it will try to get from the MX records of the e-mail domain.

Can SMTP Be Hacked?

SMTP relay lets users send e-mails through external servers. Spammers and hackers can use an e-mail server to send spam or malware through e-mail under the guise of the unsuspecting open-relay owner.

How can I make postfix secure?

How do I enable Starttls on postfix?

Enabling TLS in the Postfix SMTP server By default, TLS is disabled in the Postfix SMTP server, so no difference to plain Postfix is visible. Explicitly switch it on with “smtpd_tls_security_level = may”.

What is SMTP Rcpttodomain?

RCPT is a command used in an electronic mail transaction. Below are the main commands used when mail is sent via SMTP. HELO – The client “signs on” to the server using the HELO command. MAIL FROM – The client must tell the server who the mail is from. RCPT TO – Who the mail is going to.