The ban exception will have the following syntax (ban remove will also have about the same syntax):
ban exception (<Ip Address without wildchar> | /a <Account Name> | <Character Name>)

Some examples:*
# will ban any IP addresses like 123.123.123.*
ban add 123.123.123.*

# will add an exception for the IP Address 123.123.123.123
ban exception 123.123.123.123

# will add an exception for the character "dummy"
# If the character "dummy" is not banned, he will be able to connect from address 123.123.123.100
ban exception dummy

# will add an exception for the account "account0"
# If this account is not banned (nor the character name he is using), he will be able to connect from address 123.123.123.100
ban exception /a account0

The structure of the ban file is changing as follows:

#--------------------- BAN FILE ---------------------------
# ban explicit ip address
/i a.b.c.d ticks_init ticks_left

# exception for the player zappa (I surely don't want to ban Zappa ;-))
/-n a.b.c.d zappa

# exception for the account frank
/-a a.b.c.d frank

# ban a sub network (not really a sub network - only the last byte maybe a wildchar)
/i a.b.c.* ticks_init ticks_left

# exception for a.b.c.e in a.b.c.* subnetwork
/-i a.b.c.* a.b.c.e

# exception for the player aaaarrrggh in a.b.c.* subnetwork
/-n a.b.c.* aaaarrrggh

# exception for the account arrggghhhh in a.b.c.* subnetwork
/-a a.b.c.* arrggghhhh

# ban the player oups
/n oups ticks_init ticks_left

# ban the account spuo
/a spuo ticks_init ticks_left

# old ban player burp
burp _ ticks_init ticks_left

# old ban ip address f.g.h.i
_ f.g.h.i ticks_init ticks_left
#-------------------------------------------------------