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Exchange Send connector connections count must be limited.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-221222EX16-ED-000230SV-221222r961155_ruleCCI-001095low
Description
This setting controls the maximum number of simultaneous outbound connections allowed for a given SMTP Connector and can be used to throttle the SMTP service if resource constraints warrant it. If the limit is too low, connections may be dropped. If the limit is too high, some domains may use a disproportionate resource share, denying access to other domains. Appropriate tuning reduces the risk of data delay or loss.
STIGDate
Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide2024-12-06

Related Frameworks

1 mapping across 4 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (2) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

CAP-02Resource Priority
0.50
CAP-03Capacity Planning
0.50
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (13) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-17(10)Authenticate Remote Commands
1.00
AC-17(9)Disconnect or Disable Access
1.00
AC-3Access Enforcement
1.00
AC-4Information Flow Enforcement
1.00
AU-3Content of Audit Records
1.00
CM-6Configuration Settings
1.00
CM-7Least Functionality
1.00
CM-7(2)Prevent Program Execution
1.00
SC-47Alternate Communications Paths
1.00
SC-5Denial-of-service Protection
1.00

+3 more (top 10 by confidence shown)

CCI1 mapping
CCI-001095
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 4 hops (1) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

PR.IR-04
0.50

Details

Check Text (C-221222r961155_chk)

Review the Email Domain Security Plan (EDSP). Determine the value for SMTP Server Maximum Outbound Connections. Open the Exchange Management Shell and enter the following command: Get-TransportService | Select Name, Identity, MaxOutboundConnections If the value of "MaxOutboundConnections" is not set to "1000", this is a finding. or If the value of "MaxOutboundConnections" is set to a value other than "1000" and has signoff and risk acceptance in the EDSP, this is not a finding.

Fix Text (F-22926r411793_fix)

Update the EDSP to reflect the value for SMTP Server Maximum Outbound Connections. Open the Exchange Management Shell and enter the following command: Set-TransportService -Identity <'IdentityName'> -MaxOutboundConnections 1000 Note: The <IdentityName> value must be in single quotes. or The value as identified by the EDSP that has obtained a signoff with risk acceptance.