Central Source NAT (SNAT) and Destination NAT (DNAT/VIP)

My video about differences between profile and policy mode brought out some very important questions about central NATing. This video dives into what central Source NAT and Destination NAT (also known as Virtual IP) are and the benefits of it.

You can run central NAT in either mode, profile or policy. Policy mode forces you to use it while you have the option on profile mode to use standard or central NAT.

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[FortinetGuru]

Do you use central SNAT and DNAT? Tell us about your setups as well as the pros and cons you have experienced while utilizing this!

[TheDervMan]

We use both SNAT and DNAT extensively. DNAT allows us to expose external services provided by third parties using an IP we allocate. This simplifies inter-site routing and if the 3rd party change the IP/FQDN we simply update the DNAT. We've not used Central NAT yet but this looks very interesting 👍🏻

[Bradkid]

This video helped me understand Central NAT, but it doesn't cover that it needs to be enabled first. Still very helpful Central NAT = SNAT is my mental note.

[fooey]

Great video. Very informative!
 
Man, you're so good at explaining things. Love this channel.

[dextruded]

Mike, thanks so much. I usually read through the FortiGate documentation and call support but this video (like others) has been exceptionally helpful!

[shreeramyadav]

Thanks Mike! Can you please make few videos on CPU profiling of fortigate.

[RobbyPedrica]

For DNAT you should explain that the internal address object is now selected in the policy as destination rather than a VIP object as in non-Central nat mode ...

[qcnsllcqcnsupport]

Hey Mike, Thank You for the the videos, I really enjoy these types of videos because it helps me to learn the most. Thanks, Chris. :-)

[merlymatingou]

Good stuff. I just learned about it several weeks ago. I was initially wondering why doesn’t Fortigate have separate NAT table where I create NAT rule like the other vendor do. After researching, I found out they did. Your videos are awesome by the way. Keep up the good work.

[onuraydin]

Thanks Mike for video. I have a question. How to nat/pat to redirect any dns to a specific external ip?

[Furcas]

What exactly is source interface filtering used for on DNATs? I was thinking it was if you were specifying an incoming interface of any then target multiple ports in the filter maybe. I could see scenarios where you might have multiple uplinks from the firewall to the same internet connection.

[DannyMaas]

i'm running 6.0.x and see Central NAT still needs to be turned on in CLI, and you cannot have any VIP or IP pools configured. Wondering if that is still the case in 6.4.x. Disabling it will delete all your DNAT and VIPs. So backup if you want a go at this. ;-)

[ebosac]

Please do u have a video on vlans with internet access and url feltering

[kento]

what if there are both dnat with firewall policy with the option src-filter vip enable and central snat policy is being used from DMZ to External ( Reverse dnat direction ), which one gets priority?

[LucPaulin]

I am currently not using central nat, however that's is something I looking forward I would like to implement as it look to be much "cleaner" However something I am wondering and I haven't look at yet, would it be possible to enable central nat and have "policy nat" at the sametime, I guess not ! and therefore that become a problem when you want to change the way of doing your nating

[rajanrkv]

Hi Mate, Do we need a firewall policy for Central DNAT ? Just trying to implement it and wanted to see as i am having a bit of issue with implementing .

[anilrs]

Can we configure SNAT (IPPOOL) and Destination NAT (VIP) for the same flow in a single Fortigate FW ?

[LANACADEMY]

I have a Fortigate 100F 6.4.4 that is configured in Profile-based but Central SNAT is disabled. If I enable it would change my current NAT rules that are configured in the policies? This feature allows me to create a subnet-to-subnet deterministic mapping (1:1)?

[mdabdulmoiz]

how dnat works here is it like ASA where it unnat first then we open acl for the original ip?

[alsdmaslm]

I have a current issue that I am trying to connect to my company's NAS within my company's environment through a specific IP address through a VPN connection. But the problem is that I am stationed outside of my company, (meaning that I have a desktop in an outside environment) and there is an IP conflict for the NAS that I am trying to reach for mapping my drives. Currently I am not authorised to change the IP address of the current environment that I am in.

But I suppose NAT can be the solution that I am looking for? To translate out the ipaddress of the NAS to another IP address as it leaves the environment?