Use the Connections property page to configure transfer mode, message delivery, connection acceptance, security, retry interval, and message time-out options for the Internet Mail Service.
Use the Connections property page to configure the Internet Mail Service to accept inbound messages, send outbound messages, both, or neither. In an organization using one Internet Mail Service, you set the transfer mode to both send and receive messages. In an organization using multiple Internet Mail Services, you can balance responsibility for sending and receiving messages among the services. Use the None option when you want to suspend further message activity when preparing to remove or move the Internet Mail Service.
Note Setting the transfer mode to Inbound Only will not prevent outbound messages from being queued to this Internet Mail Service. To prevent outbound messages from being queued to this Internet Mail Service, remove the address spaces from the Address Space property page.
|Inbound & Outbound||Accept inbound and attempt outbound connections.|
|Inbound Only||Only accept inbound connections.|
|Outbound Only||Only attempt outbound connections.|
|None (Flush Queues)||Do not accept inbound connections. Pending messages are delivered.|
Use the Connections property page to specify the maximum number of inbound and outbound connections the Internet Mail Service will accept and initiate respectively at one time. You can also define the maximum number of messages sent during each connection and adjust the number of connections and messages based on resources available in your environment. Some mail systems can accept only one connection at a time. The maximum number of combined inbound and outbound connections cannot exceed 1,000.
Note Setting the maximum number of inbound and outbound connections to 0 does not stop the Internet Mail Service from accepting inbound or attempting outbound connections. For more information, see "Specifying Inbound and Outbound Transfer Modes" earlier in this chapter.
If you have a server supporting Post Office Protocol version 3 (POP3) or Internet Message Access Protocol Version 4rev1 (IMAP4) clients, you may need to increase the maximum number of simultaneous SMTP connections. POP3 and IMAP4 clients need to create an SMTP connection to the Internet Mail Service to send mail, but the number of simultaneous connections required varies based on the number and type of POP3 and IMAP4 clients.
Tip Use the Windows NT Performance Monitor to view current connections.
|Max no. of Inbound Connections||The maximum number of inbound connections the Internet Mail Service can accept at one time.|
|Max no. of Outbound Connections||The maximum number of outbound connections the Internet Mail Service can make at one time.|
|Max no. of Connections to a single host||The maximum number of connections the Internet Mail Service can make to a single host at one time.|
|Max no. of Messages sent in a connection||The maximum number of messages to be sent during each outbound connection.|
|Reset default values||Return all options to default settings.|
Use the Connections property page to specify whether all outbound messages will be routed using the routing information in the DNS. This is the default. Domains specified in outbound messages will be looked up in DNS. If the domain is found in DNS, the message will be delivered to the corresponding IP address. If the domain is not found, the message will be returned to the sender with an NDR.
For information about specifying message delivery by e-mail domain, see "Delivering Messages by E-mail Domain" later in this chapter. For more information about DNS, see Microsoft Exchange Server Concepts and Planning.
Use the Connections property page to specify that all outbound messages be sent to a single host. If message delivery by e-mail domain is not specified, the message is delivered using the option specified in the Message Delivery section of the Connections property page.
Note If the domain name of a host is specified, the domain name must be defined in the local Windows NT Server Hosts file or in the DNS. Otherwise, the Internet Mail Service will not start.
For information about specifying message delivery by e-mail domain, see "Delivering Messages by E-mail Domain" later in this chapter.
Use the Connections property page to define the way messages will be delivered to the destination.
Note This setting overrides the option you specified under Message Delivery.
|E-Mail Domain||Type the domain name for which you will specify delivery options. Do not use an ending period after the FQDN.|
|Use DNS||Select when messages to the specified domain should be delivered using DNS queries.|
|Forward all messages for this domain to host||Type the host name or IP address of the SMTP host that will process messages for the specified domain. If any host name cannot be resolved, the Internet Mail Service will not start and a Windows NT Event Log message will be generated. This option can be configured to process SMTP mail messages in a round-robin style. For example, you can type a comma-separated list of multiple hosts: host1,host2,host3. The first message will be sent to host1, the second message to host2, the third message to host3, the fourth message to host1, and so on.|
|Dial using||Select to use a dial-up connection. Choose one of the dial-up connections specified on the Dial-up Connections property page.|
For more information about message delivery, see "Delivering Messages Using DNS" and "Delivering All Messages to a Single Host" earlier in this chapter.
Use the Connections property page to accept connections from all secure and non-secure hosts. This is enabled by default.
Use the Connections property page to accept connections only from hosts using authentication or encryption.
Use the Connections property page to reject incoming SMTP connections from a single IP address or range of IP addresses. You can specify a range of addresses to reject and make a list of addresses that will be excluded from the restriction. To do this, specify the hosts from which you will accept mail higher in the list than the more general range of hosts from which connections will be rejected.
|IP Address||Type the IP address of the SMTP hosts that will be accepted or rejected. Use of wildcards is accomplished using the Mask field. If you are specifying only a single IP address to be rejected, you do not need to use the Mask field.|
Type the IP address mask. To control access, the IP address specified is matched against the IP address of the host that is connecting to the Internet Mail Service. The mask specifies which bits are relevant in the match. In Boolean logic, this is equivalent to exclusive-oring the addresses and then anding the result with the mask. If the result is zero, it is a match.
Therefore, any IP address in 192.11.154.n would match, where n = 1-254.
|Accept connections from this host||Select to allow the specified host to connect to the Internet Mail Service computer.|
|Only accept from this host if it uses||Select to accept connections from hosts using security. Choose Authentication, Encryption or Auth and Encrypt.|
|Reject connections from this host||Select to indicate that the specified host is not allowed to connect to the Internet Mail Service computer.|
|This host is a relay server||Select to override client security requirements in the Connections property page.|
|Clients can only submit if homed on this server||Select to allow clients to submit messages only if they have a mailbox on this server.|
|Clients can only submit if authentication account matches submission address||Select to allow clients to submit messages only if their logon account matches the address in the From field of the message.|
The Internet Mail Service can be set to wait a specified number of hours before retrying a host to which a previous connection attempt has failed. If the Internet Mail Service attempts to deliver a message to an SMTP host for which it has obtained an IP address and does not receive a response from the host, the connector attempts to reconnect after the period of time specified in the Retry interval box.
The first number in the list determines the time the Internet Mail Service will wait between the initial delivery attempt and the first retry. The second number is the amount of time the Internet Mail Service will wait between the first retry and the second retry, and so on. The last specified time interval will be repeated until either the connection is made or the specified time-out value has been reached.
|Retry interval (hrs)||
The number of hours to wait before retrying a connection to a host to which delivery has previously been attempted. Values are separated by commas. Periods may be used to indicate partial hours. No spaces are allowed. The default is
.25, .5, 1, 4.
For more information about time-out values, see "Specifying Message Time-out Values" later in this chapter.
Message time-out values can be specified for urgent (high importance), normal, and non-urgent (low importance) messages. If the time-out is reached before the message can be sent, the sender is notified with an NDR, and the message is not sent.
|Urgent message timeout (hrs)||The maximum amount of time the Internet Mail Service will try to send a message of high importance. The default is 24 hours. The maximum value is 999.|
|Normal message timeout (hrs)||The maximum amount of time the Internet Mail Service will try to send a message of normal importance. The default is 48 hours. The maximum value is 999.|
|Non-urgent message timeout (hrs)||The maximum amount of time the Internet Mail Service will try to send a message of low importance. The default is 72 hours. The maximum value is 999.|
|Urgent mail every (hrs)||Select to enable notification for messages of high importance. This is the default. Type a value for the number of hours before notification. The default is 4 hours.|
|Normal mail every (hrs)||Select to enable notification for messages of normal importance. Type a value for the number of hours before notification. When selected, the default is 12 hours.|
|Non-urgent mail every (hrs)||Select to enable notification for messages of low importance. Type a value for the number of hours before notification. When selected, the default is 24 hours.|