Zweite Philips Hue Bridge: Was ein Schmodder

Commentary, DIY/Bastelarbeiten, , ,

Seit mehreren Jahren nutze ich Lampen von Philips Hue. Natürlich nicht nur Lampen, sondern auch Relais, Steckdosen, allerlei Schalter, Taster, sowie Hue Labs, Routinen, die Integration mit IFTTT, usw. Entsprechend bin ich leider bereits bei 30 Lampen (von angepriesenen 50) an die 100 % der verbrauchten Regeln gekommen. Ok, das wurde im Hueblog schon vor längerer Zeit beschrieben.

Gut, den Drops muss ich leider lutschen, kaufte mir eine 2. Hue Bridge und gut is. Denkste. Die Integration einer 2. Bridge ist leider alles andere als gut:

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Adding some packets: RARP, SNAP, MPLS & More

Network, , , , , , , , , , ,

The other day I was searching for a trace file with a decent protocol mix that could be used to introduce a few colleagues to Wireshark. This brought me to Johannes Weber and his Ultimate PCAP.

To get a first impression of a trace file I used Wireshark’s protocol hierarchy – and boy, that’s a lot of protocols. This was not exactly what I was looking for: This single trace file holds snippets from 2014 to 2020 with a myriad of protocols and IP networks. Unfortunately, it’s nothing like the protocol mix found in a network analysis project.

Nevertheless, the trace file caught my interest as a long time Wireshark user. After nearly 20 years of network analysis, I had my own collection of traces with a few odd frames. To my big surprise, I had recorded a few protocols that are not yet part of the Ultimate PCAP.

So here is my small contribution to this collection:

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Route-Based VPN Tunnel FortiGate <-> Cisco ASA

Cisco Systems, Fortinet, IPsec/VPN, , , , , ,

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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Route-Based VPN Tunnel Palo Alto <-> Cisco ASA

Cisco Systems, IPsec/VPN, Palo Alto Networks, , , , ,

More than 6 years ago (!) I published a tutorial on how to set up an IPsec VPN tunnel between a Palo Alto Networks 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

Fortinet, NTP, , , , , ,

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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NTS Published as Standard

Authentication, NTP, , , , ,

This is a guest blogpost by Martin Langer, Ph.D. student for “Secured Time Synchronization Using Packet-Based Time Protocols” at Ostfalia University of Applied Sciences, Germany.

The Internet Engineering Task Force (IETF) published the Network Time Security protocol (NTS) as RFC 8915 on October 1, 2020. This new standard offers security mechanisms for the widely used Network Time Protocol v4 (NTPv4), which has been operated mostly unsecured until now. After almost eight years of development, global collaboration, and many interoperability tests of leading NTP software developers, NTS represents a mature security protocol. In this post, I’ll give you a short overview of the development progress of NTS and provide a list of public implementations and NTS secured time servers…

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iperf3 on a FortiGate

Bandwidth/Delay, Fortinet, Internet Access, Monitoring, , , ,

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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NTP Filtering (Delay & Blockage) in the Internet

NTP, , , , , , , ,

NTP (Network Time Protocol) messages are sometimes rate-limited or blocked entirely by Internet operators. This little-known “NTP filtering” was put into place several years ago in response to DDoS (Distributed Denial of Service) attacks. NTP filtering may drop NTP messages based on rate or message size. Let’s dig into it: Continue reading NTP Filtering (Delay & Blockage) in the Internet →

A Little Printing Please – Packet Capture

iPhone/iPad, Network, , , , , ,

Uh, I wasn’t aware of so many different printing protocols. Do you? While I was trying to solve a little printing problem I took a packet capture of three different printing variants over TCP/IP: Raw via TCP port 9100, LPD/LPR via TCP port 515, and Apple’s AirPrint which uses the Internet Printing Protocol IPP. As always, you can download this pcap and have a look at it by yourself.

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Palo Alto GRE Tunnel

Network, Palo Alto Networks, , ,

Since PAN-OS version 9.0 you can configure GRE tunnels on a Palo Alto Networks firewall. Greetings from the clouds. As always, this is done solely through the GUI while you can use some CLI commands to test the tunnel. This time Palo put a little stumbling block in there as you have to allow a GRE connection with a certain zone/IP reference. I will show how to set up such a GRE tunnel between a Palo and a Cisco router. Here we go:

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Certificate Transparency & Alternative Name Disclosure

Certificate, , , , , , ,

Maybe you’ve heard of Certificate Transparency and its log. Citing Wikipedia: “Certificate Transparency (CT) is an Internet security standard and open source framework for monitoring and auditing digital certificates.” Basically, it gives you information about any public certificate that is issued. Besides its advantages, I thought of one possible problem as it leaks all FQDNs to the public when using TLS certificates, for example from Let’s Encrypt.

A similar problem might arise when using a single X.509 certificate with a couple of DNS names (subject alternative name SAN) from which one should be kept “private”. It will be publicly known as well.

Hence I made a self-experiment in which I generated two certificates with random names, monitoring the authoritative DNS servers as well as the IPv6 addresses of those names in order to check who is resolving/connecting to otherwise unknown hostnames. Here we go:

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UK IPv6 Council Spring 2020: Incorrect Working IPv6 Clients & Networks

Conference Talks, IPv6, NTP, , , , ,

I did a short presentation at the spring 2020 roundtable of the UK IPv6 Council. The talk was about a case study I did with my NTP server listed in the NTP Pool project: For 66 days I captured all NTP requests for IPv6 and legacy IP while analyzing the returning ICMPv6/ICMPv4 error messages. (A much longer period than my initial capture for 24 hours.) Following are my presentation slides along with the results.

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SharkFest’19 EUROPE: IPv6 Crash Course

Conference Talks, IPv6, , , , , ,

I gave a session about IPv6 at SharkFest’19 EUROPE, the annual Wireshark developer and user community conference, named “IPv6 Crash Course: Understanding IPv6 as seen on the wire“. The talk is about the IPv6 basics, which are: IPv6 addresses & address assignment, link-layer address resolution, and ICMPv6. Tips for using Wireshark coloring rules and display filters round things up.

As I have not yet published the slides, here they are. Unfortunately, we were not able to record the session due to technical problems. Neither the video nor the audio. ;( Hence, here are only mere slides.

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