Tag Archives: FortiGate

How to install Palo Alto’s PAN-OS on a FortiGate

It happens occasionally that a customer has to choose between a Palo and a Forti. While I would always favour the Palo for good reasons, I can understand that the Forti is chosen for cost savings, for example.

Fortunately, there is a hidden way of installing PAN-OS, the operating system from Palo Alto Networks, on FortiGate hardware firewalls. Here’s how you can do it:

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Optimized NAT46 Config on a FortiGate

Johannes published a basic NAT46 configuration for a Fortigate firewall with FortiOS 7.0 some time ago. I run such a service (legacy IPv4 access to IPv6-only resources) since FortiOS 5.6, which means more than six years; lastly with FortiOS 6.4. It’s running for more than 100 servers without any other problems as we see them with IPv4 only or dual stack services.

But we weren’t happy with the basic configuration example by Fortinet. We wanted some NAT46 sample configuration with more details, that is: including the original source IPv4 address within the synthesized/SNATted IPv6 address. More in this post, after a short story about my way to a running nat46 configuration with port forwarding in FortiOS 7.2.x.

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Accessing IPv6-only Resources via Legacy IP: NAT46 on a FortiGate

In general, Network Address Translation (NAT) solves some problems but should be avoided wherever possible. It has nothing to do with security and is only a short-term solution on the way to IPv6. (Yes, I know, the last 20 years have proven that NAT is used everywhere every time. ?) This applies to all kinds of NATs for IPv4 (SNAT, DNAT, PAT) as well as for NPTv6 and NAT66.

However, there are two types of NATs that do not only change the network addresses but do a translation between the two Internet Protocols, that is IPv4 <-> IPv6 and vice versa. Let’s focus on NAT46 this time. In which situations is it used and why? Supplemented by a configuration guide for the FortiGates, a downloadable PCAP and Wireshark screenshots.

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Publishing IPv6 NTP Servers with DHCPv6

During the last weeks, I had an interesting request to publish NTP servers to client systems by using DHCPv6 in an IPv6 only network. Our Fortigate (or me?) had to learn how to publish the information. Hence this post is not only about NTP and IPv6, but a small guide on how to walk through RFCs and how to get out the relevant information. I’m very happy I got the possibility to share my experience here. Thank you, Johannes!

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Route-Based VPN Tunnel FortiGate <-> Cisco ASA

More than 6 years ago (!) I published a tutorial on how to set up an IPsec VPN tunnel between a FortiGate firewall and a Cisco ASA. As time flies by, ASA is now able to terminate route-based VPN tunnels (which is great!), we have IKEv2 running everywhere and enhanced security proposals. Hence, it’s time for an update:

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FortiGate bug: firewalls sending excessive requests to the NTP Pool

The NTP Pool is a volunteer organization that provides time synchronization service to hundreds of millions of computers worldwide. A typical client might query a particular NTP Pool server ~10-60 times/hour. Wikipedia lists some abusive clients that far exceeded the normal rate. This wastes NTP server resources, may interfere with other clients, and can trigger DDoS protections. In late 2019, a software update made some FortiGate firewalls very unfriendly to the NTP Pool.

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iperf3 on a FortiGate

This is a really nice feature: you can run iperf3 directly on a FortiGate to speed-test your network connections. It’s basically an iperf3 client. Using some public iperf servers you can test your Internet bandwidth; using some internal servers you can test your own routed/switched networks, VPNs, etc. However, the maximum throughput for the test is CPU dependent. So please be careful when interpreting the results. Here we go:

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Using a FortiGate with a 6in4 Tunnel

For some reason, I am currently using a FortiGate on a location that has no native IPv6 support. Uh, I don’t want to talk about that. ;) However, at least the FortiGate firewalls are capable of 6in4 tunnels. Hence I am using the IPv6 Tunnel Broker from Hurricane Electric again. Quite easy so far.

But note, as always: Though FortiGate supports these IPv6 features such as a 6in4 tunnel or stateful/-less DHCPv6 server, those features are NOT stable or well designed at all. I had many bugs and outages during my last years. Having “NAT enabled” on every new IPv6 policy is ridiculous. Furthermore, having independent security policies for legacy IP and IPv6 is obviously a really bad design. One single policy responsible for both Internet protocols is a MUST. Anyway, let’s look at the 6in4 tunnel:

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Fortinet FortiGate (not) using NTP Authentication

A security device such as a firewall should rely on NTP authentication to overcome NTP spoofing attacks. Therefore I am using NTP authentication on the FortiGate as well. As always, this so-called next-generation firewall has a very limited GUI while you need to configure all details through the CLI. I hate it, but that’s the way Fortinet is doing it. Furthermore the “set authentication” command is hidden unless you’re downgrading to NTPv3 (?!?) and it only supports MD5 rather than SHA-1. Not that “next-generation”!

Finally, you have no chance of knowing whether NTP authentication is working or not. I intentionally misconfigured some of my NTP keys which didn’t change anything in the NTP synchronization process while it should not work at all. Fail!

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Trying to change an IPv6 Link-Local Address on a FortiGate

I got an email where someone asked whether I know how to change the link-local IPv6 addresses on a FortiGate similar to any other network/firewall devices. He could not find anything about this on the Fortinet documentation nor on Google.

Well, I could not find anything either. What’s up? It’s not new to me that you cannot really configure IPv6 on the FortiGate GUI, but even on the CLI I couldn’t find anything about changing this link-local IPv6 address from the default EUI-64 based one to a manually assigned one. Hence I opened a ticket at Fortinet. It turned out that you cannot *change* this address at all, but that you must *add* another LL address which will be used for the router advertisements (RA) after a reboot (!) of the firewall. Stupid design!

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MP-BGP Capture

For those who are interested in analyzing basic BGP messages: I have a trace file for you. ;) It consists of two session establishments as I cleared the complete BGP session on two involved routers for it. Refer to my previous blog post for details about the lab, that is: MP-BGP with IPv6 and legacy IP, neighbouring via both protocols as well, with and without password. The involved routers were 2x Cisco routers, one Palo Alto Networks firewall, and one Fortinet FortiGate firewall.

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Basic MP-BGP Lab: Cisco Router, Palo Alto, Fortinet

While playing around in my lab learning BGP I configured iBGP with Multiprotocol Extensions (exchanging routing information for IPv6 and legacy IP) between two Cisco routers, a Palo Alto Networks firewall, and a Fortinet FortiGate firewall. Following are all configuration steps from their GUI (Palo) as well as their CLIs (Cisco, Fortinet). It’s just a “basic” lab because I did not configure any possible parameter such as local preference or MED but left almost all to its defaults, except neighboring from loopbacks, password authentication and next-hop-self.

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Route- vs. Policy-Based VPN Tunnels

There are two methods of site-to-site VPN tunnels: route-based and policy-based. While some of you may already be familiar with this, some may have never heard of it. Some firewalls only implement one of these types, so you probably don’t have a chance to configure the other one anyway. Too bad since route-based VPNs have many advantages over policy-based ones which I will highlight here.

I had many situations in which network admins did not know the differences between those two methods and simply configured “some kind of” VPN tunnel regardless of any methodology. In this blogpost I am explaining the structural differences between them along with screenshots of common firewalls. I am explaining all the advantages of route-based VPNs and listing a table comparing some firewalls regarding their VPN features.

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