Does the Internet Mail Connector Support uucp?
No, uucp is not supported in Microsoft Exchange Server
4.0. However, many service providers offer SMTP dial-up solutions
that can be used with the Internet Mail Connector.
What kind of connection do I need to get from
my service provider?
The Internet Mail Connector needs to be able to establish
a TCP connection to your service provider's SMTP host. Therefore,
any connection that supports TCP/IP services can be used, such
as PPP or SLIP over phone lines or ISDN. When selecting the kind
of connection that will be used you should consider the amount
of Internet e-mail traffic you anticipate having, and make sure
the bandwidth of the connection will be able to support it.
What must my service provider do to support a
dial-up SMTP connection?
Your service provider must configure their SMTP host
to act as a relay host for your domain. That means they must configure
a DNS MX record that instructs all hosts to connect to their server
to send mail to your domain. Their host must be configured to
hold mail for your domain until your system dials in to retrieve
it. Typically, your system will have to issue a command to their
server when it connects to trigger it to deliver any mail it has
How do I trigger my service provider's SMTP host
to deliver my mail?
This will depend on your service provider. If they
are using sendmail, there is a command option to force sendmail
to process all queued items for a recipient address. You can use
rsh to remotely execute this on the service provider's
rsh host "/usr/lib/sendmail
Some service providers use other mechanisms to trigger
mail delivery, such as issuing a finger command to a certain address.
Ask your service provider for specific instructions on how to
trigger mail delivery.
How do I configure my system to dial in to the
To use the Internet Mail Connector with a dial-up
connection, create a batch file that initiates the connection
and runs the Internet Mail Connector service to transfer mail.
You can use the Microsoft Windows NT® schedule service to execute
this batch file at specified intervals. See the Windows NT Online Help
for information on using the schedule service.
The batch file must perform the following operations:
- Initiate the PPP/SLIP connection to your service
provider. If you are using a dial-on-demand router, this step
is not necessary.
- Start the Internet Mail Connector service.
- Trigger the service provider's SMTP host to deliver
- Wait several minutes to allow inbound and outbound
delivery to complete. The amount of time to wait depends on the
maximum message size you want to allow.
- Stop the Internet Mail Connector service.
- Terminate the PPP/SLIP connection.
The Windows NT rasdial command can be used to initiate
and terminate the connection. Below is an example of a batch file
that manages a dial-up connection:
rasdial "My Provider"
if errorlevel 1 goto callfail
net start "Microsoft
Exchange Internet Mail Connector"
if errorlevel 1 goto startfail
rsh host "/usr/lib/sendmail
net stop "Microsoft Exchange
Internet Mail Connector"
rasdial "My Provider"
What if it takes longer to deliver a message than
my connection allows?
When the Internet Mail Connector is stopped, it allows
up to 60 seconds for any pending message deliveries to complete
before shutting down. Any messages that are not delivered within
60 seconds will be retried at the next connection. Dial-up connections
are of a fixed duration, so a message that takes longer than that
amount of time to transfer will never be delivered - the sending
host would keep retrying delivery until it eventually was returned
With a dial-up connection you should consider setting
a message size limit at the Internet Mail Connector. You should
choose the message size limit and connection duration such that
a message within the size limit can be delivered during a single
connection. The size limit will prevent the Internet Mail Connector
from trying to deliver inbound or outbound messages larger than
the specified size. Users in your site will be prevented from
sending large outgoing messages, but this will not protect against
large incoming messages, since they must be transmitted over the
connection before the Internet Mail Connector can reject them.
Check with your service provider to find out if they can limit
the sizes of messages they attempt to deliver to your domain.
How do I make sure the Internet Mail Connector
doesn't time-out when sending messages over my low-bandwidth dial-up
There are several registry values under the Internet
Mail Connector Parameters key (HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIMC\Parameters) that control time-outs:
SMTPRecvTimeout - waiting for packet transmission
SMTPWaitForAck - waiting for OK response to a command
sent to another host
SMTPWaitForBanner - waiting for HELO banner from
another SMTP host
SMTPWaitForDataBlock - waiting for the termination
to a DATA block
SMTPWaitForDataInitiation - waiting for the start
of transfer of a data block
SMTPWaitForDataTermination - waiting for a response
to the termination of a data block
SMTPWaitForMailFrom - waiting for a response to
the FROM command
SMTPWaitForRcpt - waiting for a response to the
These time-outs are specified in seconds. If a time-out
occurs, an event will be written to the Windows NT event log.
If these time-outs occur frequently, you may want to increase
them. In particular, the default setting for SMTPWaitForDataBlock
limits the data transfer for a message to 10 minutes. Over a low
bandwidth line you may want to increase this value to allow more
time for large messages to transmit.
What can I do to optimize the Internet Mail Connector's
performance over a low-bandwidth connection?
Using the Microsoft Exchange Server Administrator
application, open the Internet Mail Connector properties in the
Connections container. The Advanced Transfer Mode options on the
Connections page include settings for the maximum number of inbound
and outbound connections, and for the maximum number of messages
sent in a connection. The default settings are optimized for connections
at LAN speeds. For a dial-up connection, you should set the maximum
number of inbound and outbound connections to one each. You should
increase the maximum number of messages sent in a single connection
to a higher value, such as 50.
Performance over a low-bandwidth connection will
also be improved if you configure the Internet Mail Connector
to forward all mail to your service provider's SMTP host, and
let it perform the DNS resolutions to deliver mail to the appropriate