Tag Archives: Legacy IP

Palo Packet Capture: Choosing the Right Filter

Palo Alto firewalls have a nice packet capture feature. It enables you to capture packets as they traverse the firewall. While you might be familiar with the four stages that the Palo can capture (firewall, drop, transmit, receive), it’s sometimes hard to set the correct filter – especially when it comes to NAT scenarios. (At least it was hard for me…)

I am using the packet capture feature very often for scenarios in which the IP connections are in fact working (hence no problems at the tx/rx level nor on the security policy/profile) but where I want to verify certain details of the connection itself. I’m simply using the Palo as a capturing device here, similar to a SPAN port on a switch. (Yes, I’m aware of all disadvantages of not using a real TAP and a real capture device.) In the end, I want a single pcap which shows all relevant packets for a client-server connection, even if NAT is in place. Wireshark should be able to correlate the incoming/outgoing packets into a single TCP stream. Furthermore, I definitely want to use a filter to limit the amount of captured packets. This is how I’m doing it:

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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 screenshot on this blog. However, it sometimes 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 is summarizing *all* previous ones from my blog and even adding some more protocols and details. I will constantly add more packets to this pcap if I have some. Currently, it has > 60 different protocols and hundreds of variants, such as IPv6 and legacy IP traffic, different DNS query types, ICMP error codes, and so on.

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I Love IPv6 Addressing!

Probably the biggest prejudice when it comes to IPv6 is: “I don’t like those long addresses – they are hard to remember.” While this seems to be obvious due to the length and hexadecimal presentation of v6 addresses, it is NOT true. In the end, you’ll love IPv6 addresses in your own networks. This is why – summed up in one poster:

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NTP Authentication at Juniper ScreenOS

Yes, ScreenOS is end-of-everything (EoE), but for historical reasons I still have some of them in my lab. ;D They simply work, while having lots of features when it comes to IPv6 such as DHCPv6-PD. However, using IPv6-only NTP servers is beyond their possibilities. :(

Anyway, I tried using NTP authentication with legacy IP. Unfortunately, I had some issues with it. Not only that they don’t support SHA-1 but MD5, this MD5 key was also limited in its length to 16 characters. Strange, since ntp-keygen per default generates 20 ASCII characters per key. Let’s have a look:

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NTP Authentication on Pulse Connect Secure

I initially wanted to show how to use NTP authentication on a Pulse Connect Secure. Unfortunately, it does not support NTP over IPv6, which is mandatory for my lab. Ok, after I calmed down a bit, a configured it with legacy IP and got NTP authentication running. ;) Here’s how:

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IPv6 Upper Layer Protocol Samples

Some time ago I published a pcap that can be used to study basic IPv6 protocol messages such as ICMPv6 for Router Advertisements, Neighbor Solicitations, etc.: “Basic IPv6 Messages: Wireshark Capture“. You can use it to learn the basic IPv6 address assignment and layer 2 address resolution. However, that pcap does not include any upper layer protocols.

This time I captured a few application layer protocols that I used over IPv6 rather than over legacy IP. Common user protocols such as DNS, HTTP/S, IMAP, SMTP (with STARTTLS), as well as some network administration protocols: SSH, SNMP, and Ping. It is not that interesting at all ;) though you can use it to have some examples for Wireshark to prove that those application protocols are almost the same when run above IPv6 compared to IPv4.

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Juniper ScreenOS IPv4 vs. IPv6 Throughput Tests

And finally the throughput comparison of IPv6 and legacy IP on a Juniper ScreenOS firewall. Nobody needs this anymore since they are all gone. ;) But since I did the same speedtests for Palo Alto and FortiGates I was interested in the results here as well.

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