Inconsistent route information identified on the Tier-0 Routers on the Primary and Secondary Sites

Products

• VMware NSX

Issue/Introduction

In an NSX Federation environment, inconsistent routing configurations cause a lack of internet access or external connectivity for specific local sites e.g., Site-A.

When reviewing the routing table on the affected Tier-0  gateway, the default route points toward internal NSX addresses 169.254.32.4/169.254.32.3. 

Instead of the expected upstream BGP neighbor. Validation of the BGP neighbors  on the affected site confirms that the upstream physical network is not advertising a default route down to the Tier-0 gateway, unlike the behavior observed on working sites.

Environment

VMware NSX 

Cause

The upstream BGP neighbor (physical router) for the affected site is not configured to advertise a default route to the NSX Tier-0 gateway.

Resolution

 

• Access the configuration interface of the upstream physical router acting as the BGP neighbor for the affected site.

• Define and configure the BGP process on the physical router to advertise a default route (0.0.0.0/0) to the NSX Tier-0 gateway.

• Once the route is advertised, log in to the NSX Manager UI or utilize the NSX CLI on the edge nodes to validate the Tier-0 routing table.

• Confirm that the default route is now learned via BGP and points to the correct upstream neighbor IP, replacing the internal routing paths