Non-Internet facing send Connectors must specify a Smart Host.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-33594	Exch-2-771	SV-44014r1_rule	ECSC-1	Medium

Description
In the case of identifying a 'Smart Host' for the email environment, the connector level is the preferred location for this configuration because flow control in this routing group will be retained even if future changes occur at the Receive Connector level. A 'Smart Host' (Edge Transport Server) Role acts as an Internet Facing Concentrator for other email servers. Appropriate hardening can be applied to the Edge Transport Server (Email Secure Gateway) role rather than at multiple locations throughout the enterprise. The 'Smart Host' performs all Domain Name Service (DNS) lookups to determine mail routing and offers some proxy-type benefits. Failure to identify a 'Smart Host' could default to each email server performing its own lookups (potentially through protective firewalls). Exchange servers should not be Internet facing, and should therefore not perform any 'Smart Host' functions. They must, however, be configured to identify the server that is performing the 'Smart Host' function.

Description

In the case of identifying a 'Smart Host' for the email environment, the connector level is the preferred location for this configuration because flow control in this routing group will be retained even if future changes occur at the Receive Connector level. A 'Smart Host' (Edge Transport Server) Role acts as an Internet Facing Concentrator for other email servers. Appropriate hardening can be applied to the Edge Transport Server (Email Secure Gateway) role rather than at multiple locations throughout the enterprise. The 'Smart Host' performs all Domain Name Service (DNS) lookups to determine mail routing and offers some proxy-type benefits. Failure to identify a 'Smart Host' could default to each email server performing its own lookups (potentially through protective firewalls). Exchange servers should not be Internet facing, and should therefore not perform any 'Smart Host' functions. They must, however, be configured to identify the server that is performing the 'Smart Host' function.

STIG	Date
Exchange 2010 Hub Transport Server STIG	2013-09-30

Details

Check Text ( C-41701r2_chk )
Open the Exchange Management Shell and enter the following command: Get-SendConnector \| Select Name, Identity, SmartHosts Identify non-Internet facing connectors. If the value of 'SmartHosts' does not return the Smart Host IP Address, this is a finding.

Fix Text (F-37486r1_fix)
Open the Exchange Management Shell and enter the following command: Set-SendConnector <'SendConnector'> -SmartHosts <'IP Address of Smart Host'> -DNSRoutingEnabled $false