I have this PIX 515E (HA) with IPSEC 3DES disabled. How should I enable it? Should I need an activation key to enable it? Do I need to purchase it? What's the impact in a production firewall if I load a new activation key? How should I load it?
You can register for a free 3DES license from Cisco. Go to this link
(you need a login but i'm assuming you have one ?)
You will get a new activation key. You can load it on a production system without impact but you need to do a reboot for it to take effect.