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Explicit ARP Flushing

Note

This feature is available with bosh-release v256+ and 3232+ stemcell series.

Certain IaaSes may limit and/or disable gratuitous ARP for security reasons (for example AWS). Linux kernel performs periodic garbage collection of stale ARP entries; however, if there are open or stale connections these entries will not be cleared causing new connections to fail since they just use an existing outdated MAC address.

The Director is fully in control of when the VMs are created so it's able to communicate with the other VMs it manages and issues an explicit delete_arp_entries Agent RPC call to clear stale ARP entries.

To enable this feature:

1. Add director.flush_arp deployment manifest for the Director:

   properties:
     director:
       flush_arp: true
   

2. Redeploy the Director.