Not all clients support all opcodes..and not all opcodes are handled the same way across all clients.
If you happen to be comparing opcodes across clients, you want the label from the *.conf file to compare against the server opcode handler.
This is where most of your game play opcodes are handled:
https://github.com/EQEmu/Server/blob...ent_packet.cpp
There are features available in newer clients that are not in older, and vice-verse..the list almost certainly changes with each client.
If you happen to have an older version of python installed (mine is 2.6), this script can provide a little info on opcode-use locations:
https://github.com/EQEmu/Server/blob...de_handlers.py
You don't need to download it..just find the existing one in your local repo and execute it from there. It will create a directory with a lot of
output.
It's severely out-of-date and does not reflect all locations..but, does still appear to produce a somewhat useable output.
EDIT: Ok..it's still out-of-date..but, has been updated to the new client version naming scheme.