locally: ip route 0.0.0.0 0.0.0.0 188.8.131.52
on ospf: default-information-originate always
on eigrp: redistribute static metric 100000 1000 255 1 1500 (set you metric in according your an ambient)
on bgp: default-information originate
guide to bgp: https://learningnetwork.cisco.com/thread/41674
guide to ospf: https://learningnetwork.cisco.com/thread/122701
guide to eigrp: https://learningnetwork.cisco.com/thread/33634
There is no more detail as to which routing protocol are you using?
As @Jaderson Pessoa has mentioned you can use below commands and this will change based on the routing protocol. Also, there are many methods to perform the same.
Static Default Route: ip route 0.0.0.0 0.0.0.0 x.x.x.x --> x.x.x.x is the next hop IP
router ospf 1
router eigrp 1
redistribute static metric 100000 1000 255 1 1500
Router BGP 10
@Leo Laohoo nice Leo, thank for your suggestion.