https://github.com/hasheddan/coap-pcap
Understanding CoAP with Packet Captures.
https://github.com/hasheddan/coap-pcap
Last synced: 6 months ago
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Understanding CoAP with Packet Captures.
- Host: GitHub
- URL: https://github.com/hasheddan/coap-pcap
- Owner: hasheddan
- Created: 2023-06-21T19:39:29.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2023-06-27T11:57:15.000Z (almost 3 years ago)
- Last Synced: 2025-01-25T23:32:33.354Z (over 1 year ago)
- Homepage:
- Size: 229 KB
- Stars: 15
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# CoAP PCAP
Exploring the [Constrained Application Protocol
(CoAP)](https://datatracker.ietf.org/doc/html/rfc7252) in
[Wireshark](https://www.wireshark.org/).
## Setup
Packet captures can be loaded into Wireshark with the following command:
```
wireshark .pcapng
```
If the capture is using a secure transport, such as DTLS / UDP, credentials must
be provided in order to decrypt the CoAP messages.
### Pre-Shared Keys
If the capture is using Pre-Shared Keys (PSK), the PSK must be supplied in hex
form in the **Pre-Shared Key** field in Wireshark under **Edit > Preferences >
Protocols > DTLS** as shown below.
If running your own capture, you may convert your PSK to hex form using the
following command:
```
echo -n "YOUR_PSK_HERE" | xxd -ps -c 32
```
## Captures
Captures included in this repository, along with any relevant information and
credentials, are detailed below.
### Golioth Basics (PSK)
```
wireshark golioth_basics_psk.pcapng
```
The Golioth Basics (PSK) example uses the [Golioth
Basics](https://github.com/golioth/golioth-firmware-sdk/tree/main/examples/linux/golioth_basics)
program from the [Golioth Firmware
SDK](https://github.com/golioth/golioth-firmware-sdk) at
[v0.7.0](https://github.com/golioth/golioth-firmware-sdk/releases/tag/v0.7.0).
PSK in hex:
```
3639616631363835626139303830626539303739323237323863316539376335
```
### Golioth OTA Download (PSK)
```
wireshark golioth_ota_download.pcapng
```
The Golioth OTA Download (PSK) uses the Golioth [CoAP
CLI](https://docs.golioth.io/reference/command-line-tools/coap/coap) to download
a firmware artifact. The exact command used is provided below.
```
coap --path /.u/c/main@1.0.0 --psk-id 20230614151602-linux@blush-unexpected-fox --psk 24685dc5f1b2276a8f43008e20c0be92 --host coap.golioth.io > artifact.bin
```
PSK in hex:
```
3234363835646335663162323237366138663433303038653230633062653932
```