The NSX-T Tier-0 Gateway must be configured to have Internet Control Message Protocol (ICMP) unreachable notifications disabled on all external interfaces.
An XCCDF Rule
Description
The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Host unreachable ICMP messages are commonly used by attackers for network mapping and diagnosis.
- ID
- SV-251753r856694_rule
- Version
- T0RT-3X-000064
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
To configure a shared rule to drop ICMP unreachable messages do the following:
From the NSX-T Manager web interface, go to Security >> Gateway Firewall >> All Shared Rules.
Click "Add Rule" (Add a policy first if needed), under services select "ICMP Destination Unreachable", and then click "Apply".