First off, congratulations on considering peering at CNX, let me assure you, you will be peering with Cambodia’s finest!
So why would you want to filter ? all traffic to or from CNX is essentially free and close, really close to your destination! Just to be 100% clear we are talking about prefix filters here not IP ACL.
Okay so its free, but maybe should you filter for security reasons ? No! Why?
When a peer establishes a peering link we will verify the networks assigned to the peer with APNIC to ensure only prefixes owned by the peer can be announced to our RS, we will do the filtering so you don’t have to. If a peer is also announcing for his downstream, we even will call the downstream for permission. All prefixes you see on CNX are 100% verified to be owned by participating networks you will never get a prefix from CNX that does not belong.
Still want to filter? Okay what should you filter? We recommend that you may filter your own downstream peers if they also peer at CNX to protect your business routes. However you could also agree with your downstream to use CNX as backup route, if your link has enough capacity.
CNX is a free peering platform giving you access to networks in Cambodia, please consider your filters carefully. Do you filter prefixes on your paid upstream link? if not why filter at your free peering point?