Troubleshooting NAT operation on Loopback Interface or SVI interfaces

said0089said0089 Registered Users Posts: 1 ■□□□□□□□□□
I have one question concerning NAT operation. Indeed, i don't understand why when i haven't ip nat inside on loopback interface or SVI interface and i try to do a ping in sourcing on the SVI interface. The nat translate takes effect.

Sample Configuration

interface vlan 3
ip address! <
whithout ip nat inside on this interface

interface FastEthernet1/0
ip address
ip nat outside <
with ip nat outside
ip virtual-reassembly
duplex auto
speed auto

ip nat inside source list NAT-PRIVATE-LAN interface FastEthernet1/0 overload
ip access-list standard NAT-PRIVATE-LAN

R1#ping source vlan 3 """This ping is done without ip nat inside on interface VLAN 3""""""""""""""""""""""""""""""""

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Packet sent with a source address of
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/278/484 ms

R1#show ip nat translations
Pro Inside global Inside local Outside local Outside global

i had understood that to make the nat translation , there must be have both the nat rule but also IP nat inside and ip nat outside on the relevant interfaces ?

But a PC connected on thé port tagged on VLAN 3 will not be translated without ip nat inside on VLAN 3 ?
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