pb_sv_ban = RCON based, yes.
!subnetban = silEnT Mod feature. We had added support for it couple of weeks back for NON PB servers but since there is NO PB at all, now, it will come handy
If your server is ETPub, you can easily convert it to silEnT without loosing XP or admin. You can use the conversion tool.
http://mygamingtalk.com/forums/files...or-silent-mod/
Note: IIRC, in ETPub if you ban someone without GUID, it will ban all players. So be careful.