Class/Race Combinations not allowed

[apoptygma]

Just wondering if anyone can tell me what prevents for example an undead hunter or night elf paladin? I can change the race of a character easily by changing the value in the character DB but when changed to a combination that won't work on 'live realms' the character won't load - Is this beign enforced by the client or the server core?

[nyko]

this character will disappear from characters list in game but stay in chracters bdd. client issue. ever tested by myself.

[andreasaspenberg]

if it is a client issue a hack patch will most likely be needed.