SoftBank 304HW User Manual page 159

NAT
Convert private IP address used inside LAN to global IP address for connecting to the Internet.
Setting items are as follows:
Item
Cone
Symmetric
In Menu List, "Router Setting"
➜
"Cone"/"Symmetric" "Apply"
➜
Setting is made.
Low security but normal operation of application;
High compatibility with applications, gaming device etc.
Used for higher security gateway
"NAT"
Description
157