The connections cannot be readily monitored remotely. The activity logfile can be parsed by 3rd party tools to provide reports, but this capability is not present out-of-the-box.

Please do note however that SpamFilter has built-in failsafes to prevent DDOS attacks. The "blacklist IP cache" filter will drop any TCP connections from IPs that have attempted to send more than a certain amount of spam emails (3 by default) in a certain timeframe (10 minutes by default) will be automatically blocked for some time (60 minutes by default). All these values can be customized. This feature greatly reduces the DDOS risk.
In addition, implementing the greylist filter (which is disabled by default however as it introduces a small email delay during the first few hours after it has been enabled) will also drop TCP connections for all IPs that attempt to send emails to SpamFilter, until they have successfully retried after a few minutes.