Netmessages.h

Aryes · Post by **Aryes** » Mon Apr 10, 2006 2:33 am

Well, one of the things that people that use open surce files most fear is having people using modified clients at their server (as everyone can download sources and modify them) to have advantages over other players that use normal clients...

I have a little trick to avoid (or at least make it harder) people using custom-made clients. Here it is:

First of all, centralize your netmessages.h, make all sources use the same file. Then, open it and put the following lines:

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#include "version.h"

#define DEF_VERSIONPLUSMODIFIER    	(DEF_LOWER_VERSION % 5)//that can be whatever number you wish, 1 byte-sized numbers will work fine

#define	DEF_PLUSMSGMODIFIER_1    	0x01 + DEF_VERSIONPLUSMODIFIER
#define	DEF_PLUSMSGMODIFIER_2    	0x03 + DEF_VERSIONPLUSMODIFIER
#define	DEF_PLUSMSGMODIFIER_3    	0x09 + DEF_VERSIONPLUSMODIFIER
#define	DEF_PLUSMSGMODIFIER_4    	0x07 + DEF_VERSIONPLUSMODIFIER
#define	DEF_PLUSMSGMODIFIER_5    	0x05 + DEF_VERSIONPLUSMODIFIER

Then just add the definitions to the messages definitions, like that:

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#define DEF_NOTIFY_FORCEDISCONN    0x0B75  +DEF_PLUSMSGMODIFIER_1

 #define DEF_NOTIFY_FIGHTZONERESERVE    0x0B76  +DEF_PLUSMSGMODIFIER_2

Remember to let messages like DEF_MSGTYPE_CONFIRM, DEF_MSGTYPE_REJECT, and messages that are sent to login server unchanged (like DEF_LOGRESMSGTYPE_CONFIRM) or you will have problems when comunicating with the logserver (unless you are working with the mysql logserver I've released some time ago... in that case you can modify whatever you want).

Explanation: the messages used to comunicate through hgserver/client will have their values based on the version... making diff values every version, so people will have trouble making customized clients to conect to your server.

This is just a little gift to help people to fight against hackers. It won't stop them, but why not make their job harder?

rfvtgb · Post by **rfvtgb** » Mon Apr 10, 2006 7:06 am

just a minor bug
even with 100% skill magic
i dont seem to cast faster than not having 100% skill magic

locobans · Post by **locobans** » Tue Apr 11, 2006 2:55 am

rfvtgb wrote: just a minor bug
even with 100% skill magic
i dont seem to cast faster than not having 100% skill magic

WTF YOU SAYING NIGGA!

Good job Aryes B)

Sticked.

Drajwer · Post by **Drajwer** » Thu Apr 13, 2006 11:19 am

how to use that trick with SQL server and oryginal 3.51 client ?

Dax · Post by **Dax** » Thu Apr 13, 2006 11:22 am

Drajwer wrote: how to use that trick with SQL server and oryginal 3.51 client ?

You don't.

Windy · Post by **Windy** » Thu Apr 13, 2006 11:28 am

lol thats the whole point of the changed netmessages so that only YOUR client can connect, ppl cant just grab an original one and mod some stuff in it....if u want to use it then u have to compile a 351 clone client from diuuude and snoopy or make ur own...simple as that

Drajwer · Post by **Drajwer** » Thu Apr 13, 2006 11:42 am

So what when back to TXT is not possible? Any hex packets in client/server ?

Aryes · Post by **Aryes** » Thu Apr 13, 2006 10:56 pm

Drajwer wrote: So what when back to TXT is not possible? Any hex packets in client/server ?

If you hex the same values into client/server, no problem. What is important is to have both with the same values.

Cleroth · Post by **Cleroth** » Thu Apr 13, 2006 11:30 pm

Hexing an hundred of messages? Good luck.

KLKS · Post by **KLKS** » Fri Apr 14, 2006 12:15 am

there is another way of doing this but it takes more skills to do it

Post by **binarydata** » Fri Apr 14, 2006 12:31 am

mask the client version

KLKS · Post by **KLKS** » Fri Apr 14, 2006 3:10 am

actually no, its complex enough that ppl cant use their clients, they have to use yours

it involves an exe packer (Themida/Armadillo) which dosent allow memmory patching. and a modification to the encryption/decryption routine on HG and client side.

the client and server share a 'secret' key and the packet structure also changes a little

. so normal clients will not be able to connect.

its a concept idea and estimated to take abt 4-5 days to implement. the crucial part is the packer. u need a packer which has no unpacker and cannot be memory dumped

snoopy81 · Post by **snoopy81** » Fri Apr 14, 2006 9:08 am

the client and server share a 'secret' key and the packet structure also changes a little . so normal clients will not be able to connect.

I already know 2 servers that use this kind of protection system.

Anyways, coding in, instead of hacking into the client will improve the trick !

Aryes · Post by **Aryes** » Fri Apr 14, 2006 11:08 am

KLKS wrote: actually no, its complex enough that ppl cant use their clients, they have to use yours

it involves an exe packer (Themida/Armadillo) which dosent allow memmory patching. and a modification to the encryption/decryption routine on HG and client side.

the client and server share a 'secret' key and the packet structure also changes a little . so normal clients will not be able to connect.

its a concept idea and estimated to take abt 4-5 days to implement. the crucial part is the packer. u need a packer which has no unpacker and cannot be memory dumped

That's a really better way if you want to keep hackers away, I've messed with crypting/decrypting packets once, I think that encrypting only the messages ID's instead of encrypting the whole packets would still give a good result and a good performance on the server load.

KLKS · Post by **KLKS** » Fri Apr 14, 2006 3:18 pm

well the idea is good enough to stop hackers and hacks. only using 'authorised' clients to connect to the servers. A system like gameguard would be nice.