The NSX Tier-1 Gateway router must be configured to have all inactive interfaces removed.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
high	V-265518	SRG-NET-000019-RTR-000007	NT1R-4X-000016	SV-265518r999924_rule	2024-12-20	1

Description
An inactive interface is rarely monitored or controlled and may expose a network to an undetected attack on that interface. Unauthorized personnel with access to the communication facility could gain access to a router by connecting to a configured interface that is not in use. If an interface is no longer used, the configuration must be deleted and the interface disabled. For sub-interfaces, delete sub-interfaces that are on inactive interfaces and delete sub-interfaces that are themselves inactive. If the sub-interface is no longer necessary for authorized communications, it must be deleted.

Description

An inactive interface is rarely monitored or controlled and may expose a network to an undetected attack on that interface. Unauthorized personnel with access to the communication facility could gain access to a router by connecting to a configured interface that is not in use. If an interface is no longer used, the configuration must be deleted and the interface disabled. For sub-interfaces, delete sub-interfaces that are on inactive interfaces and delete sub-interfaces that are themselves inactive. If the sub-interface is no longer necessary for authorized communications, it must be deleted.

ℹ️ Check
From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-1 Gateways. For every Tier-1 Gateway, expand the Tier-1 Gateway. Click on the number in the Linked Segments to review the currently linked segments. For every Tier-1 Gateway, expand the Tier-1 Gateway. Expand Interfaces and GRE Tunnels, and click on the number of interfaces present to open the interfaces dialog. Review each interface or linked segment present to determine if they are not in use or inactive. If there are any linked segments or service interfaces present on a Tier-1 Gateway that are not in use or inactive, this is a finding.

ℹ️ Check

From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-1 Gateways. For every Tier-1 Gateway, expand the Tier-1 Gateway. Click on the number in the Linked Segments to review the currently linked segments. For every Tier-1 Gateway, expand the Tier-1 Gateway. Expand Interfaces and GRE Tunnels, and click on the number of interfaces present to open the interfaces dialog. Review each interface or linked segment present to determine if they are not in use or inactive. If there are any linked segments or service interfaces present on a Tier-1 Gateway that are not in use or inactive, this is a finding.

✔️ Fix
To remove a stale linked segment from a Tier-1 Gateway, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Segments and edit the target segment. Under Connected Gateway, change to "None" and click "Save". Note: The stale linked segment can also be deleted if there are no active workloads attached to it. To remove a stale service interface from a Tier-1 Gateway, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-1 Gateways >> Edit the target Tier-1 gateway. Expand "Interfaces and GRE Tunnels", then click on the number of interfaces present to open the interfaces dialog. On the stale service interface, select "Delete" and click "Delete" again to confirm.

✔️ Fix

To remove a stale linked segment from a Tier-1 Gateway, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Segments and edit the target segment. Under Connected Gateway, change to "None" and click "Save". Note: The stale linked segment can also be deleted if there are no active workloads attached to it. To remove a stale service interface from a Tier-1 Gateway, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-1 Gateways >> Edit the target Tier-1 gateway. Expand "Interfaces and GRE Tunnels", then click on the number of interfaces present to open the interfaces dialog. On the stale service interface, select "Delete" and click "Delete" again to confirm.