KENET has re-introduced authentication on their portal for those using the KENET-Sponsored Telkom Sim Cards. 
The login credentials as as follows 
Username :  Mobile Number without the leading zero e.g. 776037743@kenet.ac.ke 
Password:  Use the last six (6) digits of the serial number on the SIM card
For those who might have Eduroam accounts can use them for the above service.

Find attached the User guide for the service.