Threat Defense VPN Advanced IPsec Options

Advanced > IPsec > IPsec Settings

Enable Fragmentation Before Encryption
This option lets traffic travel across NAT devices that don’t support IP fragmentation. It doesn’t impede the operation of NAT devices that do support IP fragmentation.
Path Maximum Transmission Unit Aging
Check to enable Path Maximum Transmission Unit (PMTU) Aging, the interval to reset the PMTU of a Security Association (SA).
Value Reset Interval
Enter the number of minutes at which the PMTU value of an SA is reset to its original value. Valid range is 10 to 30 minutes, default is unlimited.