Restriction to send sms from defined IP-Range

[Kuppi]

Hi all,
i don't no how to restrict the access for user, wich are send sms via 
http,  to allow sending sms only  from a  predefined IP Range.
What  is the exact syntax for the setting  in the sendsms-user Group.
It would be of great help to me.
Thanks in advance

by Kuppi

Below my Group-Settings:

group = sendsms-user
username = blabla
password = blubblub
#user-deny-ip = "*.*.*.*"
user-allow-ip = "192.168.1.0/25"
max-messages = 3
concatenation = true
forced-smsc = Test