Huawei optical fiber interface cannot nat.

Huawei optical fiber interface itself does not affect nat function, because nat is a function of network equipment, which is used to realize address conversion between internal network and external network, so that internal network equipment can access public network. You have encountered the problem that the fiber interface can't NAT, which is caused by your router or firewall settings. Please check the settings of your router or firewall to ensure that it supports and turns on NAT. You still can't solve the problem. Please contact the network equipment manufacturer or technical support personnel for consultation and assistance.