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Cisco CCNA 1.9 Cisco CCST Networking 2.3 Cisco CCST Networking 5.2 CompTIA Network+ 3.4 Cisco CCNA 1.8 CompTIA Network+ 5.5 CompTIA A+ Core 1 2.6
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DEMO: Wireshark, IPv6 Packet Headers

This content covers how to capture and analyze IPv6 web traffic using Wireshark, with a focus on reading the fields inside an IPv6 packet header.

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About this video

Wireshark provides a direct way to observe how IPv6 traffic behaves on a real network, and this content uses a live capture on an Ethernet interface to demonstrate exactly that. HTTP traffic is generated by browsing to an IPv6 address, and a display filter using the ipv6.address field isolates only the relevant packets exchanged between two local devices, cutting through background noise such as Cisco discovery traffic from a connected switch. The resulting capture shows the full TCP connection lifecycle alongside the HTTP GET request and server response, making it possible to trace application-layer data transfer from end to end. With the traffic isolated, the IPv6 header is examined field by field within a single HTTP packet. The version field confirms IPv6, while the source and destination addresses are displayed in their full eight-hextet format when expanded in the packet details pane. The next header field points to TCP, which is confirmed by the TCP segment visible in the layers below, and the payload length field reflects the size of the encapsulated data. Throughout the analysis, the Ethernet frame at Layer 2 remains structurally identical to what would appear in an IPv4 capture, illustrating how protocol layering allows IPv6 to replace IPv4 at Layer 3 without requiring changes to the underlying data link layer.

What you'll learn

Aligned to

Cisco CCNA
1.9 Describe IPv6 address types
1.8 Configure and verify IPv6 addressing and prefix
Cisco CCST Networking
2.3 Identify IPv6 addresses and prefix formats
5.2 Perform a packet capture with Wireshark and save it to a file
CompTIA Network+
3.4 Given a scenario, implement IPv4 and IPv6 network services
5.5 Given a scenario, use the appropriate tool or protocol to solve networking issues
CompTIA A+ Core 1
2.6 Compare and contrast common network configuration concepts

Key terms

Internet Protocol
IP
The principal communications protocol for routing packets across network boundaries.
Packet
A unit of data formatted for transmission over a network, containing a header, payload, and sometimes a trailer.
Payload
The actual data content of a packet or message, excluding headers and metadata.
Time to Live
TTL
A value in a packet that limits its lifespan on a network, preventing it from circulating indefinitely.
Network Layer
Layer 3 of the OSI model, responsible for logical addressing and routing data packets between networks.
IPv6 Header
A fixed-length 40-byte header used in IPv6 packets, containing fields such as version, traffic class, flow label, payload length, next header, hop limit, and source and destination addresses.
Hop Limit
A field in the IPv6 header that starts at a value set by the sender and is decremented by one at each router; when the value reaches zero the packet is discarded and an ICMPv6 error is sent to the source. The hop limit serves the same loop-prevention purpose as the TTL field in IPv4.
Next Header
An IPv6 header field that identifies the type of header immediately following the IPv6 header, typically indicating the Layer 4 protocol such as TCP or UDP.

Topics

Networking Wireshark Ipv6 Packet Analysis Network Protocols Ipv4 Vs Ipv6

Transcript

We're going to take a look at some web traffic and see what it looks like inside Wireshark. Specifically, we're going to look into the IPv6 header and take a look at what information is in that IPv6 header.

Capturing the Traffic

The first thing I'm going to do is open up Wireshark, and I'm going to be monitoring my ethernet connection. Once again we start seeing some Cisco traffic coming in, and that's from the switch — the switch is trying to do some discovery, and so we see that discovery that's going out that Cisco port. But what we want to do is generate some web traffic.

So I'm going to open up a browser and then I'm going to type in http colon slash, and we're going to go to an IPv6 address, so I'm going to 0 0 0 0 colon colon colon colon colon colon colon 3 to get to our server that we have, and hit enter. That's going to bring up the web page that we have. I'm going to stop collecting data at this point in time, so I'll stop this capture here. I'm going to go back and just bookmark this so in the future I can just jump straight to this. So I'm going to bookmark this, and there we have it, bookmarked.

Filtering Down to the Conversation

So then what we can do is, inside Wireshark we see all of these different frames and packets that have come across here. What I want to do is filter out some of the noise here. So I'm going to type in — in this case it's an IPv6 address, so in the past I've typed in an IPv4 address by doing ip.address; in this case it's ipv6.address — and I am going to type in then the fc00:1::3 into here so we can just look at those, and then hit enter to filter it out.

Now we're seeing just the traffic that's going between the demo laptop and the demo Pi. So we're seeing just the traffic that goes between there. We see the TCP traffic that establishes a connection here — that's the layer 4 that's establishing a connection. We see some HTTP, so now that is the application layer that is transferring data, and so this is the request. The GET right here means that this is the demo laptop reaching out and saying, I would like to get this web page. And then we see the response right here. In fact, we can look down at it line by line, and here we see the TechKnowSurge and the information that came up on that website. So we see it right there, and then it's got some additional information here, and then it closes the connection. So there's the flow of information back and forth between these two devices.

Inside the Header

Now let's take a look at what one of those headers looks like. So I'm going to take a look — maybe we do the initial request, which is this HTTP connection right here.

We can see some of the frame information and ethernet information here at the top. We open that up and just take a look, and we see that the ethernet really doesn't change, the frame doesn't really change between IPv4 or IPv6. That's going to remain the same — ethernet is still ethernet. That's one of the advantages of layers: we can develop and grow one layer without affecting all the other layers. So we've transitioned from IPv4 to IP version 6 in the layer 3, but in the layer 2 it still looks the same. We see it is going to the destination of the Raspberry Pi and it is coming from the Dell laptop, which is the demo laptop here. So that all remains the same.

From a layer 3 perspective, it's version 6, so we do see a couple differences with this. Number one, the biggest difference is it is version 6, so it's showing version 6 right here. And then we can see that the addresses are much larger as well. We've got the addresses of the two devices here. Of course it doesn't show the full thing, because it shows the reduced where it takes all the zeros out here, but if we click on it, it actually has the full number of hextets that we have right here. So there's one, two, three, four, five, six, seven, eight — so the eight different hextets that we have in that line right there.

And we have the hop limit in here, and the next header, which is TCP. We look down, and the next header is in fact TCP, we see that right here, so that pans out. And the payload length for this particular one is 451. So if we're to click down here, we can see that that takes a significant portion of this request, this packet, that's right here.

So there we see some of the components that are within an IPv6 header.

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