Go to your Tekkit Server file and then to your config. Open the NEIServer.cng with your favorite word processor. It should look like this-
#NEI Server Permissions
# Names are Comma (,) separated
# ALL, OP and NONE are special names
saved.creativeinv=, jusupov
saved.disable-dawn=false
saved.disable-dusk=false
saved.disable-midnight=false
saved.disable-noon=false
saved.disable-rain=false
saved.magnet=, webkinz38
#List of players who can use these blocks.
#Anyone not listed here will not have these blocks appear in their item panel.
#format is {itemID}:{itemDamage}
#Eg. 12:5=CodeChicken, Friend1
BannedBlocks
{
7:0=NONE
}
#List of players who can use these features.
#Eg. time=CodeChicken, Friend1
permissions
{
creative=OP
delete=OP
enchant=OP
heal=OP
item=OP
magnet=OP
notify-item=CONSOLE, OP
rain=OP
save-state=OP
time=OP
}
The "list of players who can use these blocks" is what you want to use. just type in any block's # like this: 237:0=NONE. Or if you
want to use it then type:237:0=OP.