How can I prevent users submitting a completely anonymous survey more than once. I mean if they have participated in the survey then how can I prevent them.
1) I know I can do so with the help of cookies but the user can clear of the cookies or use a different browser. Moreover another employee / user can use the same computer to submit the survey
2) I can log the IP address but in case of DHCP it is not possible. Moreover users from the same laptop will have two different IP address when they connect to LAN and when they go wireless
3) I can generate a random code say 10 character code and sent to the end user so that they will fill up the code at the start of the survey and then set the flag at the end of the submission
4) As the survey is completely anonymous it is not possible to retrieve any user information viz name, e-mail id, employee id, user id, etc. nor logging in using their intranet id and password. This is our company policy
I am more inclined to option 3, can you throw some light on how to send a unique identifier to all participants. I am using Lotus Notes as the Mail Client