Microsoft Exchange Server 2010 : Working with SMTP Connectors, Sites, and Links (part 5) - Configuring Send Connector DNS Lookups, Setting Send Connector Limits

2/24/2014 12:29:02 AM

6. Configuring Send Connector DNS Lookups

You can configure different settings for internal and external DNS lookups by configuring a Transport server's External DNS Lookups and Internal DNS Lookups properties. External DNS Lookup servers are used to resolve the IP addresses of servers outside your organization. Internal DNS Lookup servers are used to resolve IP addresses of servers inside the organization.

To configure DNS Lookup servers, complete these steps:

Start the Exchange Management Console. On an Edge Transport server, select Edge Transport. On a Hub Transport server, expand the Server Configuration node, and then select the Hub Transport node.
In the details pane, right-click the server and then select Properties.
On the External DNS Lookups tab, shown in Figure 2, specify how external lookups should be performed:
- To use DNS settings from the server's network card or cards for external lookups, select Use Network Card DNS Settings, and then choose either All Available to use all configured settings or a specific network card to use the configured settings of that card.
- To use a specific DNS server for external lookups, click Use These DNS Servers. Then type the IP address of a DNS server to use for external lookups, and then click Add. Repeat this process to specify multiple servers.
Figure 2. Configure external DNS lookups
On the Internal DNS Lookups tab, specify how internal lookups should be performed:
- To use DNS settings from the server's network card or cards for internal lookups, select Use Network Card DNS Settings and then choose either All Available to use all configured settings or a specific network card to use the configured settings of that card.
- To use a specific DNS server for internal lookups, click Use These DNS Servers. Then type the IP address of a DNS server to use for internal lookups, and then click Add. Repeat this process to specify multiple servers.
Click OK to save your settings.

7. Setting Send Connector Limits

Send connector limits determine how mail is delivered after a connection has been established and the receiving computer has acknowledged that it's ready to receive the data transfer. After a connection has been established and the receiving computer has acknowledged that it's ready to receive the data transfer, Exchange Server attempts to deliver messages queued for delivery to the computer. If a message can't be delivered on the first attempt,Exchange Server tries to send the message again after a specified time. Exchange Server keeps trying to send the message at the intervals you've specified until the expiration time-out is reached. When the time limit is reached, the message is returned to the sender with a nondelivery report (NDR). The default expiration time-out is two days.

After multiple failed attempts to deliver a message, Exchange Server generates a delay notification and queues it for delivery to the sender of the message. Notification doesn't occur immediately after failure. Instead, Exchange Server sends the delay notification message only after the notification delay interval and then only if the message hasn't already been delivered. The default delay notification is 4 hours.

With SMTP, you have much more control over outgoing connections than you do over incoming connections. You can limit the number of simultaneous connections and the number of connections per domain. These limits set the maximum number of simultaneous outbound connections. By default, the maximum number of connections is 1,000 and the maximum number of connections per domain is 20.

You can view or change the Send connector limits by completing the following steps:

Start the Exchange Management Console. On an Edge Transport server, select Edge Transport. On a Hub Transport server, expand the Server Configuration node, and then select the Hub Transport node.
In the details pane, right-click the server and then select Properties.
On the Limits tab, shown in Figure 3, use the following options for retrying unsuccessful outbound connections:
- Outbound Connection Failure Retry Interval (Minutes) Sets the retry interval for subsequent connection attempts to a remote server where previous connections have failed. The default is 10 minutes.
- Transient Failure Retry Interval (Seconds) Sets the interval at which the server immediately retries when it encounters a connection failure with a remote server. The default is 300 seconds.
- Transient Failure Retry Attempts Sets the maximum number of times that the server immediately retries when it encounters a connection failure with a remote server. The default is six. If you enter 0 as the number of retry attempts or the maximum number of attempts has been reached, the server no longer immediately retries a connection and instead waits according to the outbound connection failure retry interval.
When messages that cannot be delivered reach the Maximum Time Since Submission value, they expire, and Exchange Server generates a nondelivery report. To set the expiration time-out for messages, enter the desired message expiration value in the Maximum Time Since Submission (Days) text box. The default expiration time-out for messages is two days.

Figure 3. Configure connection limits.
When messages are delayed longer than the allowed delay interval, Exchange Server sends a delay notification to the sender. To set the amount of time to wait before notifying senders of a delay, enter the desired wait time in the Notify Sender When Message Is Delayed More Than (Hours) text box. The default wait time is four hours.
To remove outgoing connection limits, clear the Maximum Concurrent Outbound Connections check box. To set an outgoing connection limit, select the Maximum Concurrent Outbound Connections check box, and then type the limit value. The default limit is 1,000 outbound connections.
To remove outgoing connection limits per domain, clear the Maximum Concurrent Outbound Connections Per Domain check box. To set an outgoing connection limit per domain, select the Maximum Concurrent Outbound Connections Per Domain check box, and then type the limit value. The default limit is 20 outbound connections per domain.
Click OK to save your settings.