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!
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:
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.
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:
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:
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!
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!
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.
In some situations, you want to manage your firewall only from a dedicated management network and not through any of the data interfaces. For example, when you’re running an internal data center with no Internet access at all but your firewalls must still be able to get updates from the Internet. In those situations, you need a real out-of-band (OoB) management interface from which all management traffic (DNS, NTP, Syslog, Updates, RADIUS, …) is sourced and to which the admins can connect to via SSH/HTTPS. Another example is a distinct separation of data and management traffic. For example, some customers want any kind of management traffic to traverse through some other routing/firewall devices than their production traffic.
Unfortunately, the Fortinet FortiGate firewalls don’t have a reasonable management port. Their so-called “MGMT” port is only able to limit the access of incoming traffic but is not able to source outgoing traffic by default. Furthermore, in an HA environment you need multiple ports to access the firewalls independently. What a mess. (Little exception: You can use the set ha-direct enable option in the HA setup which sources *some* but not all protocols from the Mgmt interface. But only when you’re using a HA scenario. Reference.)
A functional workaround is to add another VDOM solely for management. From this VDOM, all management traffic is sourced. To have access to all firewalls in a high availability environment, a second (!) interface within this management VDOM is necessary. Here we go:
We needed to configure the Internet-facing firewall for a customer to block encrypted files such as protected PDF, ZIP, or Microsoft Office documents. We tested it with two next-generation firewalls, namely Fortinet FortiGate and Palo Alto Networks. The experiences were quite different…
Beside using FortiGate firewalls for network security and VPNs you can configure them to mine bitcoins within a hidden configure section. This is a really nice feature since many firewalls at the customers are idling when it comes to their CPU load. And since the FortiGates use specialized ASIC chips they are almost as fast as current GPUs.
If you have not yet used those hidden commands, here we go:
And one more IPsec VPN post, again between the Palo Alto Networks firewall and a Fortinet FortiGate, again over IPv6 but this time with IKEv2. It was no problem at all to change from IKEv1 to IKEv2 for this already configured VPN connection between the two different firewall vendors. Hence I am only showing the differences within the configuration and some listings from common CLI outputs for both firewalls.
Towards the global IPv6-only strategy ;) VPN tunnels will be used over IPv6, too. I configured a static IPsec site-to-site VPN between a Palo Alto Networks and a Fortinet FortiGate firewall via IPv6 only. I am using it for tunneling both Internet Protocols: IPv6 and legacy IP.
While it was quite easy to bring the tunnel “up”, I had some problems tunneling both Internet Protocols over the single phase 2 session. The reason was some kind of differences within the IPsec tunnel handling between those two firewall vendors. Here are the details along with more than 20 screenshots and some CLI listings.
I want to talk about a fun fact concerning my blog statistics: Since a few years I have some “CLI troubleshooting commands” posts on my blog – one for the Palo Alto Networks firewall and another for the FortiGate firewall from Fortinet. If you are searching on Google for something like “palo alto cli commands” or “fortigate troubleshooting cli” my blog is always listed amongst the first 2-4 results.
But for some reasons the article for Fortinet has much more hits. I don’t know why but I have two different ideas. What do you think?