TLS argument allows selecting how a client and an SMTP server negotiates the version of TLS or SSL to be used in secure connection when using SSL or STARTTLS commands. This mechanism allows selecting a stronger, a weaker, or just a preferred version of secure protocol.

While it is usually not necessary to choose the TLS version, it may come handy to explicitly exclude some outdated security standards such as SSL v3, and allow only the newest TLS v1.1 and TLS v1.2 standards. If no TLS argument is specified, the operating system chooses the best possible value for a particular SMTP server.

Command syntax

  • febootimail -TLS 1.0
  • febootimail -TLS 1.0 -TLS 1.1
  • febootimail -TLS 1.2 -TLS 1.3
  • febootimail -TLS 1.2 -TLS SSLv3
  • febootimail -TLS SSLv3

Febootimail allows choosing the following TLS versions: 1.0, 1.1, 1.2, 1.3, or SSLv3. Febootimail also supports the latest TLS standard v1.3 on recent Windows 10 and Windows Server 2019 updates, if it is enabled in OS configuration. To let the operating system choose the best TLS version, use ANY (or ALL) value for the TLS parameter. This is also a default parameter when none is specified.

  • febootimail -TLS ALL
  • febootimail -TLS ANY
febootimail -TLS 1.2 -TLS SSLv3 -SUBJ Secured email using CMD -FROM -TO -TEXT Sending secure email with custom TLS options -SMTP reports.db.local -SSL

The registry settings take precedence over the TLS argument. For example, if SSL3 is disabled in the Windows registry, it cannot be enabled using this argument. Likewise, TLS 1.3 support can be enabled or disabled in the Windows registry on recent versions of Windows.

Related commands

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