VPN: What does the Enable Fragmented Packet Handling' checkbox do?

Question:

What does the ‘Enable Fragmented Packet Handling’ checkbox do?

Answer:

For various reasons, IPsec traffic can become fragmented in transit. If this checkbox is not enabled, then fragmented IPsec traffic will get dropped. If you are experiencing problems with traffic not successfully passing across VPN tunnels, please enable this feature. In SonicOS Enhanced 3.1.0.7 and newer, and SonicOS Standard 3.1.0.7 and newer, this checkbox is enabled by default.