Managing the Hub Transport Server Role • Chapter 6 347 Figure 6.25 Specifying the Source Server TIP To create a Send connector via the Exchange Management Shell, you must use the New-SendConnector cmdlet. For example, to create a Send Connector similar to the one we generated in the previous steps, run the following command: New-SendConnector –Name ‘To ISP (Smart host)’ –Usage ‘Internet’ –AddressSpaces ‘smtp: * .exchangehosting.dk;1’ –DNSRoutingEnabled $true –UseExternalDNSServersEna bled $false –SourceTransportServers ‘EDFS03’. 8. On the Confi guration Summary page, make sure you confi gured the connector as required, and then click Next. 9. On the Completion page, click Finish. 348 Chapter 6 • Managing the Hub Transport Server Role When you have created a Send connector, you can disable, enable, modify, and remove it by selecting the respective Send connector, and then choosing the required tasks in the Action pane. Confi guring DNS Lookups You can confi gure a Hub Transport server to use different settings for external and internal DNS lookups. Click the Properties of your Hub Transport server under the Server Confi guration | Hub Transport work center node. On the External DNS Lookups tab shown in Figure 6.26, specify that DNS server(s) should be used to resolve IP addresses of servers outside your organization. As you can see, you have the option of using the DNS settings confi gured for one of the network cards in the server, or by specifying the IP address of the DNS server(s) directly. You have the exact same options available under the Internal DNS Lookups tab. The only difference is that under this tab you specify the DNS server(s) that should be used to resolve IP addresses of servers inside your organization. Figure 6.26 Confi guring External DNS Lookups Managing the Hub Transport Server Role • Chapter 6 349 Confi guring Outbound Message Limits You can confi gure how the Hub Transport server should process outbound messages. This is done by opening the Property page of the respective Hub Transport server object in the Result pane. Here, you click the Limits tab. As you can see in Figure 6.27, you have the option of setting the retry interval— in other words, how often the Hub Transport server should try to resend an outbound message to a destination server, which for some SMTP servers don’t accept the message the fi rst time it’s sent. Figure 6.27 Confi guring Outbound Message Limits Under Message expiration, we can specify the amount of days a message held locally in a message queue as undeliverable should expire. As you can see, the default setting is 2 days, wherein the message will be removed from the message queue and a non-delivery report (NDR) will be sent to the sender of the message. 350 Chapter 6 • Managing the Hub Transport Server Role In addition, we can specify after how many hours a non-deliver report (NDR) should be generated and delivered to the sender of the message. By default, the sender will be notifi ed every fourth hour. Finally, we can confi gure connection restrictions for concurrent outbound connections and concurrent outbound connections per domain. Unless you’re dealing with a very large organization, you should leave the connection restrictions at their defaults. Typically, the default settings should be suffi cient for most organizations, but if you’re in a situation where you need to adjust them a little, this is the place to do it. Receive Connectors A Receive connector represents an inbound connection point for SMTP, and controls how a Hub Transport server receives messages over SMTP. No Receive connector, no inbound mail. This means that in order for a Hub Transport server to receive messages from the Internet (from e-mail clients as well as other e-mail servers), at least one Receive connector is required. When you install the Hub Transport server role on a server, two Receive connectors are created by default. A Client <servername> and a Default <servername> receive connector, as shown in Figure 6.28. These two connectors are required in order for internal mail fl ow to work. Figure 6.28 Default Receive Connectors Managing the Hub Transport Server Role • Chapter 6 351 A Receive connector only listens for connections that match the settings confi gured on the respective connector. That is, connections that are received through a specifi c local IP address and port, and from a particular IP address range. Receive connectors are local to the Hub Transport server on which they’re created. This means that a receive connector created on one Hub Transport server cannot be used by another Hub Transport server in the organization. So, by creating Receive connectors, you can control which server should receive messages from a particular IP address or IP address range. In addition, you can create custom connector properties for messages arriving from a particular IP address or IP address range. You could, for example, allow larger message sizes, more recipients per message (both of these will be covered later in this chapter) or perhaps more inbound connections. Creating a Receive Connector To create a Receive connector, you must perform the following steps: 1. Open the Exchange Management Console and select Hub Transport under the Server Confi guration work center node (shown back in Figure 6.28). 2. In the Result pane, select the Hub Transport server on which you want to create the Receive connector. 3. Now click New Receive Connector in the Action pane. 4. The New SMTP Receive Connector wizard will appear. Type a descriptive name for the connector, and select the type of connector you want to create. As can be seen in Figure 6.29, you can select between fi ve different Receive connector types: ■ Custom This option is used to create customized Receive connectors, which are used to connect with systems that are not Exchange servers. NOTE By default, a Hub Transport server only accepts inbound messages from other Transport servers (that is, Hub Transport and Edge Transport servers) that are part of the Exchange organization, authenticated Exchange users, and internal legacy Exchange servers (Exchange 2000 and 2003). This means that e-mail servers that are external to the organization by default cannot deliver messages to a Hub Transport server. The reason behind this decision is to make Hub Transport servers secure out of the box by default. “But isn’t it a little too aggressive to not allow inbound messages from the Internet?” I hear some of you grumble. Well, perhaps it is, but since the Exchange Product group is convinced that all organizations around the globe will deploy an Edge Transport server in their perimeter networks, the Exchange Product Group doesn’t see this as an issue at all. Luckily, it’s a rather painless process to allow untrusted e-mail servers (that is, e-mail servers not part of the Exchange organization except the Edge Transport server) to deliver messages directly to a Hub Transport server. I’ll show you how in the section titled “Confi guring the Hub Transport Server as an Internet-Facing SMTP Server” later in this chapter. . is, Hub Transport and Edge Transport servers) that are part of the Exchange organization, authenticated Exchange users, and internal legacy Exchange servers (Exchange 2000 and 2003). This means. Send connector, and then choosing the required tasks in the Action pane. Confi guring DNS Lookups You can confi gure a Hub Transport server to use different settings for external and internal DNS. and delivered to the sender of the message. By default, the sender will be notifi ed every fourth hour. Finally, we can confi gure connection restrictions for concurrent outbound connections and