09-24-2018 07:21 PM - edited 02-21-2020 08:16 AM
NAT cmds below will nat source & dest to which network-X or net-Y or net-Z? What is the reason so many identical "nat (inside,any) source static net-10.1.1.0 net-10.1.1.0" But with different "net-X net-X"?
nat (inside,any) source static net-10.1.1.0 net-10.1.1.0 destination static net-172.1.10 net-172.1.10 no-proxy-arp route-lookup
nat (inside,any) source static net-10.1.1.0 net-10.1.1.0 destination static net-172.27.0.0 net-172.27.0.0 no-proxy-arp route-lookup
nat (inside,any) source static net-10.1.1.0 net-10.1.1.0 destination static net-172.25.0.0 net-172.25.0.0 no-proxy-arp route-lookup
09-24-2018 09:38 PM
09-25-2018 12:31 AM
09-25-2018 04:00 PM
1. You need to interpret that way:
Source traffic from 10.1.1.0/24 on inside zone (i assume all your subnets are /24) to destination 172.1.10.0/24 (no matter which zone) will result after Nat with source 10.1.1.0/24 to destination 172.1.10.0/24
As you can understand, the traffic won't be natted.
2. nat (inside,any) source static net-10.1.1.0 net-10.1.1.0 destination static net-172.1.10 net-172.1.10 no-proxy-arp route-lookup
We can say this is a no nat rule because the real subnet and translated subnet are equal for source and destination.
The first net-10.1.1.0 is real source and the second net-10.1.1.0 is the translated source. Same applies for the destination group.
3. After these 3 nat rules, you have a dynamic natting traffic over outside interface. This means, if traffic won't hit the first 3 rules then it's being transferred with outside interface ip to be able to access Internet.
Also, it's not recommended to keep Nat with any statement.
09-25-2018 07:32 PM
09-26-2018 02:02 PM
09-24-2018 10:56 PM
Hello,
These NAT statements are bidirectional, which means that any traffic trying to reach out to a specific destination will check that NAT statement. For example, the first NAT will hit when the destination is net-172.1.10 subnet. And ofcourse NAT will happen as per the Double NAT:
Check this document:
Please note that this is a twice NAT, means that this will work for reverse traffic as well. The document will make things clear.
HTH
AJ
09-25-2018 12:35 AM
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