As Claudiu mentioned, the key here is to decrypt the traffic first. For that you need to have an SSL Policy, this can found under Polcies>Access Contro> SSL. Key things to have in mind when deciding to decrypt SSL traffic:
- There some web apps who DO NOT LIKE you decrypting the traffic. (i.e. Office 365). It is key that you add the respective SSL polices to Not Decrypt this traffic. You can use certificates CNs to white-list the traffic. O365 is just an example, you will need to observe your network so you know which applications will need to be white-listed
- I would recommend to only decrypt traffic of interest and not all traffic. The more decryption/resigning you have going on, the bigger the hit on performance. I wouldn't go too crazy if you are just running a 5506.
- Be sure you have distributed the firewall's Certificate to your clients (computers, servers) before you put an SSL policy in play.
Once you create SSL policy, you need to assign it to your Access Control Policy. When you open your Policy you will see on the top an option that says "SSL Policy:" here you can assign the policy you just created.
Lastly, a lot can go wrong with SSL decryption if not done right. Although I have done on a few appliances, I always run tests on each environment before production.
