Category Archives: Vendor/Device/OS

Getting started with the APIs from Palo Alto Ntwks

You can talk to firewalls and Panorama from Palo Alto Networks in various ways. The well-known GUI (which I really love, by the way) and the CLI are quite common at first glance. Nearly everyone using the Palos is familiar with these configuration options.

When it comes to automation at some point, either to configure those devices or just to read out some KPIs for your monitoring, APIs are in place. Plural because Palo has two APIs: The so-called “XML API” and the “REST API“. Let’s get started with both of them:

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iPad Ping: WLAN vs. LAN

Meine Kids spielen derzeit häufig Brawl Stars, ein Echtzeit Onlinespiel. Und sie schauen auch immer mal Videos dazu, bei denen ihnen jetzt der Floh ins Ohr gesetzt wurde, dass man ein iPad ja auch per LAN-Adapter mit einem Netzwerkkabel ausstatten kann, was ja den Ping verbessert.

JAAAA, endlich waren meine Kenntnisse in Sachen Netzwerktechnik mal von meinen Kindern gefragt. “Papa, weißt du, was ein LAN-Kabel ist?” “Ja klar.” “Hast du so eines?” “Ja, circa Hundert.” “Waaas? Echt jetzt? Dann muss ich mir ja gar keins kaufen.” 😂

Neben der Subjektivität, ob das Zocken per LAN-Kabel jetzt merklich besser wird, wollte ich mal objektiv messen, wie sich die Latenz eines per Ethernet-Adapter angeschlossenen iPads denn nun wirklich verhält. Wie viel besser wird der Ping im Idle- bzw. im Volllastfall? Was sagt die Laufzeit zum Default Gateway? Hier ein paar Tests:

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PANW: Dynamic Routing between Logical Routers

How to route traffic between multiple logical routers aka Inter-LR Routing on a Palo Alto Networks Strata firewall? More precisely, inclusive route redistribution rather than a few static routes. –> Via iBGP through loopback interfaces. ✅ Let’s go:

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BGP Route Filtering with Palo’s Advanced Routing Engine (ARE)

With PAN-OS 10.2, Palo Alto Networks has introduced the “Advanced Routing Engine” (ARE) with its “Logical Routers” (LR) rather than the legacy “Virtual Routers” (VR).

The Advanced Routing Engine simplifies operations with a standards-based configuration, which reduces your learning curve since it is similar to that of other router vendors.

The neat thing, as always: You can configure everything through the GUI. Here’s a basic example of how I’m using a prefix list to filter incoming BGP routes:

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Misusing Palo’s Captive Portal as a Guest Wi-Fi Welcome Page

I was faced with an interesting customer requirement: An existing guest Wi-Fi should be prefaced with a welcome page for accepting the terms and conditions. Since there was already a Palo Alto Networks firewall in place, could we perhaps use its captive portal directly for this purpose? It’s not about authenticating the users, but only for a single webpage with a simple check button that should appear once a month per device.

TL;DR: While we were able to redirect every device to a welcome page, we were not able to extend the lifetime of those sessions to longer than 24 hours. This might fit for short-term guest Wi-Fis, but is not appropriate for long-term connections aka BYOD. However, this is how we have done it:

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Dynamic DNS on a Palo

With PAN-OS 9.0 (quite some time ago), Palo Alto Networks has added Dynamic DNS for a firewall’s interfaces. That is: If your Internet-facing WAN interface gets a dynamic IP address via DHCP or PPPoE (rather than statically configured), the firewall updates this IP address to a configured hostname. The well-known DynDNS providers such as Dyn (formerly DynDNS), No-IP, or FreeDNS Afraid are supported. Since the Palo supports DHCP, PPPoE (even on tagged subinterfaces) as well as DHCPv6 respectively PPPoEv6, we can now operate this type of firewall on residential ISP connections AND still access it via DNS hostnames. Great. Let’s have a look at the configuration steps.

Spoiler: The DynDNS feature on a Palo only supports static IPv6 addresses rather than dynamic ones. 🤦🤦🤦 Yes, you haven’t misread. The DYNAMIC DNS feature does not support DYNAMIC IP addresses, but only STATIC ones. D’oh!

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Palo’s Mgmt-Intf is not usable with IPv6 anymore

Wow, that was unexpected: With PAN-OS 11.1 the out-of-band management interface of Palo Alto Networks firewalls doesn’t accept an IPv6 default route pointing to one of its own data interfaces anymore. That is: In most setups, you can’t use IPv6 for management purposes anymore. “Works as expected.” Wow. Really?

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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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DHCPv6 Prefix Delegation on Palo Alto’s NGFW

Finally! With PAN-OS 11.0 a long missing IPv6 feature was introduced: DHCPv6-PD aka prefix delegation. For the first time, we can now operate a PAN-OS firewall directly on the Internet (the IPv6-Internet that is) on many kinds of ISP connections. Remember: To get a routed IPv6 prefix requires DHCPv6-PD (if you’re not a BGP-homed enterprise). Hence, without that feature, we could not connect to the Internet with a Palo directly.

With DHCPv6-PD, the firewall can receive a prefix from the ISP (commonly a /48 or a /56), while handing out /64s to downstream layer 3 interfaces. Here we go:

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Contributing to Wireshark (without any coding skills!)

For many years I was afraid to open new issues for open-source tools since I am not a coder at all and won’t ever be able to fix some of the problems. Many times I got answers like “The source is open, go ahead and fix it yourself”. This brought me to a point where I simply stopped proposing new ideas and features.

This has changed since I was at SharkFest’22 EUROPE (the Wireshark Developer and User Conference), especially at a session from Uli Heilmeier called “Contribute to Wireshark – the low hanging fruits” [PDF].

TL;DR: You don’t need to be a programmer to contribute to Wireshark! E.g., submit new feature requests, report bugs or write at the wiki.

And that is exactly what I would like to recommend to you. This post is about giving examples, that even minor errors and thoughts are appreciated by the Wireshark team. But, of course, if you actually have coding skills, please go ahead and fix some of the issues. ;)

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Basic NTP Client Test on Windows: w32tm

When implementing NTP servers, it’s always an interesting part to check whether the server is “up and running” and reachable from the clients. While I’ve done many basic NTP checks out of Linux, I lacked a small docu to do this with Windows. It turned out that there’s no need for third-party software because Windows already includes a tool to test NTP connections: w32tm.

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Minor Palo Bug: ICMPv6 Errors sourced from Unspecified Address

During my IPv6 classes, I discovered a (minor) bug at the NGFW from Palo Alto Networks: ICMPv6 error messages, such as “time exceeded” (type 3) as a reply of traceroute, or “destination unreachable” (type 1) as a reply of a drop policy, are not correctly sourced from the IPv6 address of the data interface itself, but from the unspecified address “::”. Here are some details:

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Meinberg LTOS: “syslog-ng” and the Observed Implementation Pitfalls

Meinberg, with the great help of Mr Weber, has implemented “syslog over TLS” in the LTOS version 7.06. The following report describes the general advantages of “syslog over TLS” and the implementation of it in the LTOS.

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