To better understand survey access restrictions, let's talk about how the overall process works. People can only access your survey if:
a) it is active and the submission limit has not been reached
b) they have a link to your survey
Activation is easy. Configure the survey, tweak all details, specify the dates when it should be active, and turn it on. Distributing the link is just as easy. Pick which segment you want to distribute (main one by default), copy your survey link and send away. Unless people have a link to your survey, it is very unlikely that they will be able to guess the unique survey code and submit responses to it.
If you want to further enhance survey security, there are several options available to you in the setup screen:
1. Password. You can specify a password that people will need to enter before they can get into the survey. That password can be distributed separately to prevent unauthorized access.
2. Secure connection (SSL). You can force survey submission process to be performed over SSL. This is the same standard technology that is used to power online banking systems that prevents eavesdropping.
3. You can specify IP address(es) to include or exclude from survey submission. If you want people to only submit this survey while on company's network, this is how you can force it.
4. Prevent multiple submissions from the same computer. You can enforce 1 and only 1 submission from a particular computer to prevent duplicates.