In Windows you can't limit the number of connections from 1 user.
Windows Firewall doesn't have a feature where you can limit the number of connections originating from 1 ip address.
If you want that you'd have to switch to a more professional firewall.
If you'd run Subsonic under IIS you could use the feature Dynamic IP Restictions as described at
https://www.iis.net/downloads/microsoft/dynamic-ip-restrictionsBut than you'd be also facing the problem of blocking one user who connects to your server using different ISP's ( e.g. 4G and Broadband Internet Connection) thus using different Ip addresses.
The only way to restict a user from abusing his access to your server would be by limiting the bitrate ( Settings >> User >> Max. Bitrate 32 Kbps). Limiting the bitrate also means that that user won't be using much bandwith from your internetconnection.
Another option would be to delete that user completely.
