Email is still the most common communication protocol on the Internet. And since I was missing some variants of the related protocols, IMAP, POP3, and SMTP in the Ultimate PCAP, I did some captures. ✅ Here are a few details.
Tag Archives: Ultimate PCAP
More Capture Details III
Another update of the Ultimate PCAP is available. Again, there are some special new packets in there which I want to point out here. Feel free to download the newest version to examine those new protocols and packets by yourself. Featuring: SNMPv3, WoL, IPMI, HSRP, Zabbix, Pile of Poo, and Packet Comments. ✅
Stateful DHCPv6 Capture (along with Relaying)
For my IPv6 training classes, I was missing a capture of a stateful DHCPv6 address assignment. That is: M-flag within the RA, followed by DHCPv6 messages handing out an IPv6 address among others. Therefore, I set up a DHCPv6 server on an Infoblox grid and furthermore used a Palo Alto NGFW as a DHCPv6 relay to it. I captured on two points: from the client’s point of view (getting to the relay) and from the server’s point of view (unicast messages from the relay). And since I was already there anyway, I additionally captured the same process for DHCPv4. So, here we go:
Continue reading Stateful DHCPv6 Capture (along with Relaying)
RADIUS & TACACS+ PCAP
Again two more commonly used network protocols for the Ultimate PCAP: the Remote Authentication Dial-In User Service (RADIUS) and the Terminal Access Controller Access-Control System Plus (TACACS+) protocols. Captured with quite some details:
Who sends TCP RSTs?
At SharkFest’22 EU, the Annual Wireshark User and Developer Conference, I attended a beginners’ course called “Network Troubleshooting from Scratch”, taught by the great Jasper Bongertz. In the end, we had some high-level discussions concerning various things, one of them was the insight that TCP RSTs are not only sent from a server in case the port is closed, but are also commonly sent (aka spoofed) from firewalls in case a security policy denies the connection. Key question: Can you distinguish between those spoofed vs. real TCP RSTs? Initially, I thought: no, you can’t, cause the firewalls out there do a great job.
It turned out: you can!
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.
Continue reading Accessing IPv6-only Resources via Legacy IP: NAT46 on a FortiGate
Linux’s Traceroute
The other day I just wanted to capture some basic Linux traceroutes but ended up troubleshooting different traceroute commands and Wireshark display anomalies. Sigh. Anyway, I just added a few Linux traceroute captures – legacy and IPv6 – to the Ultimate PCAP. Here are some details:
More Capture Details II
An updated version of my Ultimate PCAP is available. It features some more network protocols that I will depict in this blog post. It’s getting more special since the most common protocols were already in there. ;)
More Capture Details
In the previous post, I released my Ultimate PCAP which includes every single pcap I had so far on my blog. But that’s not all: I have some packets in there that were not yet published up to now. That is, here are some more details about those (probably well-known) protocols. These are:
The Ultimate PCAP
For the last couple of years, I captured many different network and upper-layer protocols and published the pcaps along with some information and Wireshark screenshots on this blog. However, it always takes me some time to find the correct pcap when I am searching for a concrete protocol example. There are way too many pcaps out there.
This is supposed to change now:
I’m publishing a single pcap meant to be a single point of source for Wireshark samples. It summarises *all* previous ones from my blog and even adds some more protocols and details. I will constantly add more packets to this pcap if I have some. Currently, it has 80+ different protocols and hundreds of variants, such as IPv6 and legacy IP traffic, different DNS query types, ICMP error codes, and so on.