IF you want to restrict TYPO3 backend side then you have to set below line in your “localconf.php” file.
$TYPO3_CONF_VARS['BE']['IPmaskList'] = 'XXX.X.XXX.XXX,XX.XXX.XX.XXX,XX.XXX.XXX.XX';
XXX.X.XXX.XXX is stand for IP address.
You can set more than one IP address by comma seprated.
If you have any queries, please do not hesitate to contact me at Jainish Senjaliya