Setting-up Palo Alto Firewall without NAT Policy

hibagus — Sun, 15 Oct 2017 11:36:00 GMT

Dear all,

I am a newbie and currently at the first phase to learn Palo Alto Firewall. I am setting-up a simple virtual network topology using VMWare Workstation as follows.

As you can see from the diagram, there are two zones which are labeled as Trust and Untrust with network 192.168.250.0/24 and 192.168.150.0/24 respectively. The ETH1/1 is facing to the Trust Zone and has IP address 192.168.250.10 where the ETH1/2 is facing to the Untrust Zone and has IP address 192.168.150.10.

My first approach for basic configuration is as follows.

1. Configure the Management Interface on 192.168.100.10. I can access it both from web browser and from SSH on Management PC.

2. Configure ETH1/1 and ETH1/2 IP address

3. Create Zone labeled as Trust and Untrust then assign them to ETH1/1 and ETH1/2 respectively.

4. Create Virtual Router named Default for ETH1/1 and ETH1/2 and set a static route as follows

- Name: Default

- Destination: 0.0.0.0/0

- Interface: None

- Next Hop: IP Address 192.168.150.2

- Metric: 10

- Route Table: Unicast

5. Add new Security Policies as follows

- Name: Internet Access

- Type: Universal

- Source: Zone Trust, Address Any, User Any, HIP Profile Any

- Destination: Zone Untrust, Address Any

- Application: Any

- Service: Any

- Action: Allow

- Profile: None

6. Add new NAT Policies as follows

- Name: Default

- Source: Zone Trust, Address Any, Service Any

- Destination: Zone Untrust, Address Any, Service Any

- Source Translation: Dynamic IP and Port, Interface ETH1/2, IP 192.168.150.10/24

- Destination Translation: None

With this configuration, the Trust PC can access internet. Moreover, using the CLI on the PA-VM, I can ping 8.8.8.8 from both side.

ping source 192.168.150.10 host 8.8.8.8

ping source 192.168.250.10 host 8.8.8.8

My question is, can I achieve the same without using NAT? I just want to configure the firewall without NAT so that I can demonstrate the access policy between the Untrust PC to access some resource in Trust PC. When I disable the NAT policy, I cannot ping the 8.8.8.8 from 192.168.250.10 side but I can ping the 8.8.8.8 from 192.168.150.10 side.

Any help would be highly appreciated

Thank you.

Sincerely,

Bagus.

Re: Setting-up Palo Alto Firewall without NAT Policy

mgarg — Wed, 18 Oct 2017 00:43:59 GMT

the reason why you are not able to get to internet, once you disable the nat policy , is because your modem does not know how to reach 192.168.250.0/24 network for the return packet and hence it would drop it.

Add route on your modem to route traffic for 192.168.250.0/24 to 192.168.150.10

Re: Setting-up Palo Alto Firewall without NAT Policy

Mick_Ball — Sun, 15 Oct 2017 20:27:30 GMT

Add a static route to your modem.

192.168.250.0/24. Via 192.168.150.10

Re: Setting-up Palo Alto Firewall without NAT Policy

hibagus — Wed, 18 Oct 2017 01:46:03 GMT

Hi mgarg, Thank you for reply.

Since the router is a virtual router NAT in VMWare Workstation, I am currently unable to find the solution to add the static routing. Therefore, I should implement the virtual router myself (e.g. using Ubuntu VM). By the way, your solution works as expected!

Thank you.

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