Synchronization and Auto-Summary

The synchronization setting controls whether the router advertises routes learned from an iBGP neighbor based on the presence of those routes in its IGP. When synchronization is enabled, BGP will only advertise routes that are reachable through OSPF or RIP (the Exterior Gateway Protocols as opposed to BGP, the Exterior Gateway Protocol). Synchronization is a common cause of BGP route advertisement problems.

The auto-summary setting controls whether or not routes are advertised classfully. Auto-summary is another common cause of BGP configuration problems

By default, auto-summary and synchronization are disabled on Zebos.