Open Browser and Enter the IP address of pfSense firewall … Suppose your firewall ip is 192.168.1.1
Then Following login screen will appear ….
Enter user Name and Password …. Default User name : Admin and Password is : pfsense
Now Go in System Menu and Click on “Routing” follow in Screen Shot ….
Now Routing Screen appears …. Click on “Edit” Which you want WAN or Internet Connection Default ….
In Edit you Can See there Is check Box for ” Default Gateway “….
Now Click on Check Box then Save Button
Now Click on Apply Changes … and now You Can Notice there is changed the Gateway ….