Exchange of messages such as version, getaddr, and getdata can be seen in the following example along with the appropriate comment describing the message name.
This exercise can be very useful in order to learn Bitcoin protocol and it is recommended that the experiments be carried out on the Bitcoin testnet ( ), where various messages and transactions can https://en.bitcoin.it/wiki/Testnet be sent over the network and then be analyzed by Wireshark.
A Complete Guide to Understanding This Blockchain Concept
Wireshark is a network analysis tool
The analysis performed by Wireshark in the following screenshot shows the exchange of messages between two nodes.
If you look closely, you’ll notice that top three messages show the node discovery protocol that we have discussed before: Node discovery protocol in Wireshark Full clients are thick clients or full nodes that download the entire blockchain; this is the most secure method of validating the blockchain as a client.
Bitcoin network nodes can operate in two fundamental modes: full client or lightweight SPV client.
SPV clients are used to verify payments without requiring the download of a full blockchain.
SPV nodes only keep a copy of block headers of the current valid longest blockchain.
Why This Matters for Blockchain Technology
Verification is performed by looking at the Merkle branch that links the transactions to the original block the transaction was accepted in.
This is not very practical and requires a more practical approach, which was implemented with BIP 37 ( ), where bloom filters were used to filter out relevant https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki transactions only.
Bloom filter is basically a data structure (a bit vector with indexes) that is used to test the membership of an element in a probabilistic manner.
It basically provides probabilistic lookup with false positives but no false negatives.
Key Points to Remember
- Exchange of messages such as version, getaddr, and getdata can be seen in the following example along with the appropriate comment describing the message name.
- This exercise can be very useful in order to learn Bitcoin protocol and it is recommended that the experiments be carried out on the Bitcoin testnet ( ), where various messages and transactions can https://en.bitcoin.it/wiki/Testnet be sent over the network and then be analyzed by Wireshark.
- Wireshark is a network analysis tool
- The analysis performed by Wireshark in the following screenshot shows the exchange of messages between two nodes.
Going Deeper: Advanced Concepts
It means that this filter can produce an output where an element that is not a member of the set being tested is wrongly considered to be in the set, but it can never produce an output where an element does exist in the set, but it asserts that it does not.
Elements are added to the bloom filter after hashing them several times and then set the corresponding bits in the bit vector to 1 via the corresponding index.
In order to check the presence of the element in the bloom filter, the same hash functions are applied and compared with the bits in the bit vector to see whether the same bits are set to 1.
Not every hash function (such as SHA-1) is suitable for bloom filters as they need to be fast, independent, and uniformly distributed.
Conclusion
commands represents one of the many innovative layers that make blockchain technology so powerful and transformative. As distributed systems continue to evolve, a solid understanding of these core concepts becomes increasingly valuable — not just for developers, but for anyone building, investing in, or working alongside blockchain-powered systems.
Whether you are just starting your blockchain journey or deepening existing expertise, mastering these fundamentals gives you the tools to think clearly about decentralized systems and make smarter decisions in this rapidly evolving space.