! ==========================================
! Router ISP (Simulated Internet Service Provider)
! Lab: IPv4 Dynamic PAT at the Edge (PTL-0020)
! ==========================================
enable
configure terminal
hostname ISP

! WAN Interface to Customer Edge Router R1
interface GigabitEthernet0/0/0
 description WAN Transit Link to R1
 ip address 203.0.113.2 255.255.255.252
 duplex auto
 speed auto
 no shutdown
 exit

! Public Server Segment
interface GigabitEthernet0/0/1
 description Public Server LAN
 ip address 198.51.100.1 255.255.255.0
 duplex auto
 speed auto
 no shutdown
 exit

! Note: ISP maintains only public connected routes.
! No routing entries exist for RFC 1918 private space (192.168.10.0/24).

end
copy running-config startup-config