Adtran
TA900e(config)# ip firewall
TA900e(config)# ip access-list standard PUBLIC
TA900e(config-std-nacl)# permit any
TA900e(config-std-nacl)# exit
TA900e(config)# ip policy-class PRIVATE
TA900e(config-policy-class)# nat source list PUBLIC address 1.1.1.1 overload
TA900e(config-policy-class)# exit
TA900e(config)# interface eth 0/1
TA900e(config-eth 0/1)# access-policy PRIVATE
TA900e(config-eth 0/1)# exit
TA900e(config)# write mem
Cisco
router# config t
router(config)# int fast 0/0
routerconfig-if)# ip nat inside
router(config-if)# int fast 0/1
router(config-if)# ip nat outside
router(config-if)# exit
router(config)# access-list 20 remark NAT Overload
router(config)# access-list 20 permit 192.168.1.0 0.0.0.255
router(config)# ip nat inside source list 20 interface fast 0/1 overload
router(config)# do write mem