Technical Tip: Cease/Maximum Number of Prefixes Reached BGP Error

When troubleshooting BGP neighbor relationship issues, it is possible to see the following error message after running the following debugs: 

Enable BGP debugs: 

diagnose ip router bgp all enable

diagnose ip router bgp level info

diagnose debug enable

BGP: %BGP-3-NOTIFICATION: received from 10.10.10.10 6/1 (Cease/Maximum Number of Prefixes Reached.) 0 data-bytes []

This error message is a result of the local peer advertising more routes than the configured limit on the remote peer.

To verify what routes are being advertised to a neighbor:

get router info bgp neighbors <neighbor IP> advertised-routes

To address this issue, it is possible either to:

1. Increase the limit of how many advertised routes can be accepted on the peer's end (more than likely not feasible as in some networks with BGP there can be a large number of routes which may cause performance issues).
   
   
2. From the local peer, configure route maps or prefix lists to filter what routes are being advertised under the neighbor configuration:
   config router prefix-list | config router route-map 

For further information on creating prefix lists/route maps: 

• Technical Tip: How to control BGP route advertisement with prefix-list 
• Technical Tip: Create an Access-list on a Route-Map that would deny specific network on a BGP peering 
• Technical Tip: How to check BGP advertised and received routes on a FortiGate

3. Apply route map or prefix list to the particular neighbor:
   config router bgp 
       config neighbor 
           edit  <neighbor IP>
               set route-map-out <route_map_name>

               set route-map-in<route_map_name>
               set prefix-list-in <prefix_list_name>
               set prefix-list-out <prefix_list_name>
       end 
   end 
   
   

Related article: 

Troubleshooting tips for FortiOS routing (RIP, OSPF, BGP, static routes, ECMP)