interface Dialer1 (or FastEthernet0)
ip nat outside
interface Vlan 1
ip nat inside
ip nat inside source list TONAT interface Dialer1 overload
ip nat inside source static 192.168.1.2 203.87.57.205
Port forwarding:
ip nat inside source static tcp 192.168.1.2 25 203.87.57.205 25 extendable
ip access-list extended TONAT
permit ip 192.168.1.0 0.0.0.255 any
permit ip 192.168.1.0 0.0.0.255 any
Thoubleshooting:
show ip nat translationsclearip nat translation *
sh ip nat statistics
sh ip nat statistics