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Establish a connection with a server.
Syntax
object.Connect( [RemoteHost],
[RemotePort], [UserName], [Password],
[Timeout], [Options] )
Parameters
- RemoteHost
- A string which specifies the host name or IP address of the
server. If this argument is not specified, it defaults to the
value of the HostAddress property if it is defined.
Otherwise, it defaults to the value of the HostName
property.
- RemotePort
- A number which specifies the port to connect to on the server.
If this argument is not specified, it defaults to the value
of the RemotePort property. A value of zero specifies that
the default port number should be used. For standard connections,
the default port number is 25. An alternative port is 587, which is
commonly used by authenticated clients to submit messages for
delivery. For implicit SSL connections, the default port number
is 465.
- UserName
- An optional string argument which specifies the user name to be
used with authentication. If this argument is not specified, it
defaults to the value of the UserName property. Note that
for authentication to be performed, the Extended property
must be set to True.
- Password
- An optional string argument which specifies the password to be
used with authentication. If this argument is not specified, it
defaults to the value of the Password property. Note that
for authentication to be performed, the Extended property
must be set to True.
- Timeout
- The number of seconds that the client will wait for a response
before failing the operation. If this argument is not specified,
the value of the Timeout property will be used as the default.
- Options
- A numeric value which specifies one or more options. If this
argument is omitted or a value of zero is specified, a default
connection will be established. This argument is constructed by
using a bitwise operator with any of the following values:
| Value |
Constant |
Description |
| 0 |
smtpOptionNone |
No additional options are specified when establishing a
connection with the server. A standard, non-secure connection
will be used and the client will not attempt to use extended
(ESMTP) features of the protocol. Note that if the mail server
requires authentication, the smtpOptionExtended option
must be specified. |
| 1 |
smtpOptionExtended |
Extended SMTP commands should be used if possible. This
option enables features such as authentication and delivery
status notification. If this option is not specified, the
library will not attempt to use any extended features. This
option is automatically enabled if the connection is
established on port 587 because submitting messages for
delivery using this port typically requires client
authentication. |
| &H400 |
smtpOptionTunnel |
This option specifies that a tunneled TCP connection and/or
port-forwarding is being used to establish the connection to
the server. This changes the behavior of the client with
regards to internal checks of the destination IP address and
remote port number, default capability selection and how the
connection is established. |
| &H800 |
smtpOptionTrustedSite |
This option specifies the server is trusted. The
server certificate will not be validated and the connection
will always be permitted. This option only affects connections
using either the SSL or TLS protocols. |
| &H1000 |
smtpOptionSecureExplicit |
This option specifies that a secure connection should be
established with the server and requires that the server
support either the SSL or TLS protocol. This option initiates
the secure session using the STLS command. |
| &H2000 |
smtpOptionSecureImplicit |
This option specifies the client should attempt to
establish a secure connection with the server. It should only
be used when the server expects an implicit SSL connection or
does not implement RFC 2595 where the STLS command is used to
negotiate a secure connection with the server. |
| &H8000 |
smtpOptionSecureFallback |
This option specifies the client should permit the use of
less secure cipher suites for compatibility with legacy servers.
If this option is specified, the client will allow connections
using TLS 1.0 and cipher suites that use RC4, MD5 and SHA1. |
| &H40000 |
smtpOptionPreferIPv6 |
This option specifies the client should prefer the use of
IPv6 if the server hostname can be resolved to both an IPv6 and
IPv4 address. This option is ignored if the local system does
not have IPv6 enabled, or when the hostname can only be resolved
to an IPv4 address. If the server hostname can only be resolved
to an IPv6 address, the client will attempt to establish a
connection using IPv6 regardless if this option has been
specified. |
Return Value
A value of zero is returned if the connection was successful.
Otherwise, a non-zero error code is returned which indicates the
cause of the failure.
Remarks
The Connect method establishes a connection with the mail server.
All arguments are optional. If a given argument is omitted, then the
corresponding property values are used as defaults. Specifying a username
and password only sets the default UserName and Password property
values. If authentication is required, the client must explicitly call the
Authenticate method after the connection has been established.
See Also
Extended Property,
HostAddress Property,
HostName Property,
Options Property,
RemotePort Property,
Authenticate Method,
Disconnect Method,
OnConnect Event
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