@bpm91
Other thing you can do is to set custom protocol version in client and server ex. 12345 in place of 860 (8.60) and allow only clients with that protocol version. That way you can still communicate with client (Tibia client/official OTC) and tell it that 'its not allowed to connect, download official OTS client'.
If you set RSA to custom value, it will just drop connection from client on server side. Client won't get message that it's invalid and player has to use official client.
You need to know/remember that changing RSA is not a safe way to block 'other clients'.
1. If you are using Tibia client (Tibia.exe) with modified RSA, it can be easily extracted from .exe.
2. If you are using OTC, it can be easily found in .lua file.
3. If you are using OTCv8 with encryption of Lua files, it still can be easily decrypted
*
After someone extract your new RSA from client, he can put it in his client (Tibia/OTClient) and still use it to bot on your server.
*you may create/buy OTCv8 with 'custom encryption algorithm', which will make it a little harder to extract RSA, but default OTCv8 encryption can be decrypted in 30 seconds.
EDIT:
So only thing you 'force' with new RSA is telling players to use your client. You don't really block access using other client.
Only way to really block other clients is to modify Tibia protocol on server and in client (send/receive some extra bytes), so other clients won't be compatible with it. That's hard to break and only very experienced programmers will be able to find your protocol changes inside your official client .exe file.
I did it once on Kasteria.pl and cheaters did not find way to use other client.. they just made 'bot for Kasteria' that works with official OTS client
Only way to block botters is to use Cam system that record all players actions on server side and some script to analyse that on server (time between actions/number of actions/player position/health change etc.).