To send mail to another internet host also running SMTP, simply
    invoke the OpenVMS Mail utility at the DCL prompt, type SEND at
    the MAIL> prompt, and enter the destination. A remote destination
    consists of the destination user name followed by an at sign (@)
    and the destination host (such as user_name@host). If the user is
    on your local host, omit the at sign and host name.

    Specify the destination host as either a host name or an IP
    address.

    The OpenVMS Mail utility automatically detects destination
    addresses that include fully qualified host names (one in
    which the node component includes a period [.], such as
    MALCOLM@PHILOS.BU.EDU) and sends the mail using the SMTP
    protocol, unless your system has been set up to use a different
    Internet protocol (by defining an alternate protocol with the
    MAIL$INTERNET_TRANSPORT logical name).

    However, if you use a destination address that is not fully
    qualified - that is, one in which the node component does not
    include a period (.) - the Mail utility by default assumes
    the address is a DECnet address. For example, if you specified
    MALCOLM@PHILOS as the destination address, the Mail utility
    converts it to DECnet format (PHILOS::MALCOLM).

    You can force the OpenVMS Mail utility to use a specific protocol
    by defining the MAIL$INTERNET_MODE logical name. This is useful
    in cases where a mail address, such as MALCOLM@PHILOS, can be
    valid for either SMTP or DECnet.

    You can assign one of the following values to the MAIL$INTERNET_
    MODE logical name:

    o  SMTP

       OpenVMS Mail always interprets the node component of an
       unqualified address as an Internet address specification.
       (SMTP is the default mode unless you define an alternate
       Internet transport with the MAIL$INTERNET_TRANSPORT logical
       name.)

    o  DECNET

       OpenVMS Mail always interprets the node component of an
       unqualified address as a DECnet node specification.

    o  HYBRID (the default)

       OpenVMS Mail uses an Internet protocol if the node component
       of the address contains a period. If no periods are in the
       node component, Mail uses the DECnet protocol.

    Define the logical name in your LOGIN.COM file. For example, the
    following definition causes the Mail utility to interpret any
    address that does not include a period in the node component of
    the specification as an Internet address:

    $ DEFINE MAIL$INTERNET_MODE SMTP

    Another way to force the OpenVMS Mail utility to use SMTP is to
    include the SMTP% prefix immediately before the destination or
    IP address. Enclose the destination in quotation marks, as in the
    following example:

    $ MAIL
    MAIL> SEND
    To:   SMTP%"malcolm@philos"

    To prevent the OpenVMS Mail utility from automatically converting
    an unqualified Internet host name address to a DECnet format, you
    can do one of the following:

    o  Fully qualify the host name (for example, specify the
       destination address as MALCOLM@PHILOS.BU.EDU instead of
       MALCOLM@PHILOS).

    o  Define the MAIL$INTERNET_MODE logical name as SMTP.

    o  Include the SMTP% prefix before the destination address.

    For more information about the OpenVMS Mail utility and how it
    interprets addresses, see the appropriate OpenVMS documentation.