When the firewall is translating IPv4 packets in which
the DF (don’t fragment) bit is zero, that indicates the sender expects
the firewall to fragment packets that are too large, but the firewall
doesn’t fragment packets for the IPv6 network (after translation)
because IPv6 doesn’t fragment packets. Instead, you can configure
the minimum size into which the firewall will fragment IPv4 packets
before translating them. The
NAT64 IPv6 Minimum Network
MTU value is this setting, which complies with
RFC 6145,
IP/ICMP Translation Algorithm. You
can set the
NAT64 IPv6 Minimum Network MTU to
its maximum value (), which causes the
firewall to fragment IPv4 packets to the IPv6 minimum size before
translating them to IPv6. (The
NAT64 IPv6 Minimum Network
MTU does not change the interface MTU.)