Control Messages#
The following network messages all help control the connection between two peers or allow them to advise each other about the rest of the network.
Note that almost none of the control messages are authenticated in any way, meaning they can contain incorrect or intentionally harmful information.
addr#
The addr (IP address) message relays connection information for peers on the network. Each peer which wants to accept incoming connections creates an addr message providing its connection information and then sends that message to its peers unsolicited. Some of its peers send that information to their peers (also unsolicited), some of which further distribute it, allowing decentralized peer discovery for any program already on the network.
An addr message may also be sent in response to a getaddr message.
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
Varies |
IP address count |
compactSize uint |
The number of IP address entries up to a maximum of 1,000. |
Varies |
IP addresses |
network IP address |
IP address entries. See the table below for the format of a Dash network IP address. |
Each encapsulated network IP address currently uses the following structure:
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
4 |
time |
uint32 |
Added in protocol version 31402. |
8 |
services |
uint64_t |
The services the node advertised in its |
16 |
IP address |
char |
IPv6 address in big endian byte order. IPv4 addresses can be provided as IPv4-mapped IPv6 addresses |
2 |
port |
uint16_t |
Port number in big endian byte order. Note that Dash Core will only connect to nodes with non-standard port numbers as a last resort for finding peers. This is to prevent anyone from trying to use the network to disrupt non-Dash services that run on other ports. |
The following annotated hexdump shows part of an addr message. (The message header has been omitted and the actual IP address has been replaced with a RFC5737 reserved IP address.)
fde803 ............................. Address count: 1000
d91f4854 ........................... Epoch time: 1414012889
0100000000000000 ................... Service bits: 01 (network node)
00000000000000000000ffffc0000233 ... IP Address: ::ffff:192.0.2.51
208d ............................... Port: 8333
[...] .............................. (999 more addresses omitted)
addrv2#
Added in protocol version 70220 of Dash Core
The addrv2 message relays connection information for peers on the network just like the addr message, but is extended to allow gossiping of longer node addresses as described in BIP155.
Each encapsulated network IP address currently uses the following structure:
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
4 |
time |
uint32_t |
A time in Unix epoch time format. Nodes advertising their own IP address set this to the current time. Nodes advertising IP addresses they’ve connected to set this to the last time they connected to that node. Other nodes just relaying the IP address should not change the time. |
Varies |
services |
compactSize uint |
The services the node advertised in its |
1 |
networkID |
uint8_t |
Network identifier. An 8-bit value that specifies which network is addressed. Network ID types may be found in BIP155. |
Varies |
addr |
Vector<uint8_t> |
Network address. The interpretation depends on networkID. |
2 |
port |
uint16_t |
Port number in big endian byte order. Note that Dash Core will only connect to nodes with non-standard port numbers as a last resort for finding peers. This is to prevent anyone from trying to use the network to disrupt non-Dash services that run on other ports. |
The following annotated hexdump shows part of an addrv2 message. (The message header has been omitted.)
01 ................................. Address count: 1
1a2a8961 ........................... Epoch time: 1636379162
Services information
| fd ............................... Number of service bytes (2)
| 0504 ............................. Service bits: 10000000101 (network, bloom, network_limited)
Peer address details
| 01 ............................... Network ID (1 - IPv4)
| 04 ............................... Address length
| 2d20ed4c ......................... IP Address: 45.32.237.76
| 4a37 ............................. Port: 18999
filteradd#
Added in protocol version 70001 as described by BIP37.
The filteradd message tells the receiving peer to add a single element to a previously-set bloom filter, such as a new public key. The element is sent directly to the receiving peer; the peer then uses the parameters set in the filterload message to add the element to the bloom filter.
Because the element is sent directly to the receiving peer, there is no obfuscation of the element and none of the plausible-deniability privacy provided by the bloom filter. Clients that want to maintain greater privacy should recalculate the bloom filter themselves and send a new filterload message with the recalculated bloom filter.
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
Varies |
element bytes |
compactSize uint |
The number of bytes in the following element field. |
Varies |
element |
uint8_t[] |
The element to add to the current filter. Maximum of 520 bytes, which is the maximum size of an element which can be pushed onto the stack in a pubkey or signature script. Elements must be sent in the byte order they would use when appearing in a raw transaction; for example, hashes should be sent in internal byte order. |
Note: a filteradd message will not be accepted unless a filter was previously set with the filterload message.
The annotated hexdump below shows a filteradd message adding a TXID. (The message header has been omitted.) This TXID appears in the same block used for the example hexdump in the merkleblock message; if that merkleblock message is re-sent after sending this filteradd message, six hashes are returned instead of four.
20 ................................. Element bytes: 32
fdacf9b3eb077412e7a968d2e4f11b9a
9dee312d666187ed77ee7d26af16cb0b ... Element (A TXID)
filterclear#
Added in protocol version 70001 as described by BIP37.
The filterclear message tells the receiving peer to remove a previously-set bloom filter. This also undoes the effect of setting the relay field in the version message to 0, allowing unfiltered access to inv messages announcing new transactions.
Dash Core does not require a filterclear message before a replacement filter is loaded with filterload. It also doesn’t require a filterload message before a filterclear message.
There is no payload in a filterclear message. See the message header section for an example of a message without a payload.
filterload#
Added in protocol version 70001 as described by BIP37.
The filterload message tells the receiving peer to filter all relayed transactions and requested merkle blocks through the provided filter. This allows clients to receive transactions relevant to their wallet plus a configurable rate of false positive transactions which can provide plausible-deniability privacy.
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
Varies |
nFilterBytes |
compactSize uint |
Number of bytes in the following filter bit field. |
Varies |
filter |
uint8_t[] |
A bit field of arbitrary byte-aligned size. The maximum size is 36,000 bytes. |
4 |
nHashFuncs |
uint32_t |
The number of hash functions to use in this filter. The maximum value allowed in this field is 50. |
4 |
nTweak |
uint32_t |
An arbitrary value to add to the seed value in the hash function used by the bloom filter. |
1 |
nFlags |
uint8_t |
A set of flags that control how outpoints corresponding to a matched pubkey script are added to the filter. See the table in the Updating A Bloom Filter subsection below. |
The annotated hexdump below shows a filterload message. (The message header has been omitted.) For an example of how this payload was created, see the filterload example.
02 ......... Filter bytes: 2
b50f ....... Filter: 1010 1101 1111 0000
0b000000 ... nHashFuncs: 11
00000000 ... nTweak: 0/none
00 ......... nFlags: BLOOM_UPDATE_NONE
Initializing A Bloom Filter#
Filters have two core parameters: the size of the bit field and the number of hash functions to run against each data element. The following formulas from BIP37 will allow you to automatically select appropriate values based on the number of elements you plan to insert into the filter (n) and the false positive rate (p) you desire to maintain plausible deniability.
Size of the bit field in bytes (nFilterBytes), up to a maximum of 36,000:
(-1 / log(2)**2 * n * log(p)) / 8Hash functions to use (nHashFuncs), up to a maximum of 50:
nFilterBytes * 8 / n * log(2)
Note that the filter matches parts of transactions (transaction elements), so the false positive rate is relative to the number of elements checked—not the number of transactions checked. Each normal transaction has a minimum of four matchable elements (described in the comparison subsection below), so a filter with a false-positive rate of 1 percent will match about 4 percent of all transactions at a minimum.
According to BIP37, the formulas and limits described above provide support for bloom filters containing 20,000 items with a false positive rate of less than 0.1 percent or 10,000 items with a false positive rate of less than 0.0001 percent.
Once the size of the bit field is known, the bit field should be initialized as all zeroes.
Populating A Bloom Filter#
The bloom filter is populated using between 1 and 50 unique hash functions (the number specified per filter by the nHashFuncs field). Instead of using up to 50 different hash function implementations, a single implementation is used with a unique seed value for each function.
The seed is nHashNum * 0xfba4c795 + nTweak as a uint32_t, where the values are:
nHashNum is the sequence number for this hash function, starting at 0 for the first hash iteration and increasing up to the value of the nHashFuncs field (minus one) for the last hash iteration.
0xfba4c795 is a constant optimized to create large differences in the seed for different values of nHashNum.
nTweak is a per-filter constant set by the client to require the use of an arbitrary set of hash functions.
If the seed resulting from the formula above is larger than four bytes, it must be truncated to its four most significant bytes (for example, 0x8967452301 & 0xffffffff → 0x67452301).
The actual hash function implementation used is the 32-bit Murmur3 hash function.
🚧 Murmer3 Version
Warning: the Murmur3 hash function has separate 32-bit and 64-bit versions that produce different results for the same input. Only the 32-bit Murmur3 version is used with Dash bloom filters.
The data to be hashed can be any transaction element which the bloom filter can match. See the next subsection for the list of transaction elements checked against the filter. The largest element which can be matched is a script data push of 520 bytes, so the data should never exceed 520 bytes.
The example below from Dash Core bloom.cpp combines all the steps above to create the hash function template. The seed is the first parameter; the data to be hashed is the second parameter. The result is a uint32_t modulo the size of the bit field in bits.
MurmurHash3(nHashNum * 0xFBA4C795 + nTweak, vDataToHash) % (vData.size() * 8)
Each data element to be added to the filter is hashed by nHashFuncs number of hash functions. Each time a hash function is run, the result will be the index number (nIndex) of a bit in the bit field. That bit must be set to 1. For example if the filter bit field was 00000000 and the result is 5, the revised filter bit field is 00000100 (the first bit is bit 0).
It is expected that sometimes the same index number will be returned more than once when populating the bit field; this does not affect the algorithm—after a bit is set to 1, it is never changed back to 0.
After all data elements have been added to the filter, each set of eight bits is converted into a little-endian byte. These bytes are the value of the filter field.
Comparing Transaction Elements To A Bloom Filter#
To compare an arbitrary data element against the bloom filter, it is hashed using the same parameters used to create the bloom filter. Specifically, it is hashed nHashFuncs times, each time using the same
nTweak provided in the filter, and the resulting output is modulo the size of the bit field provided in the filter field. After each hash is performed, the filter is checked to see if the bit at that indexed location is set. For example if the result of a hash is 5 and the filter is 01001110, the bit is considered set.
If the result of every hash points to a set bit, the filter matches. If any of the results points to an unset bit, the filter does not match.
The following transaction elements are compared against bloom filters. All elements will be hashed in the byte order used in blocks (for example, TXIDs will be in internal byte order).
TXIDs: the transaction’s SHA256(SHA256()) hash.
Outpoints: each 36-byte outpoint used this transaction’s input section is individually compared to the filter.
Signature Script Data: each element pushed onto the stack by a data-pushing opcode in a signature script from this transaction is individually compared to the filter. This includes data elements present in P2SH redeem script when they are being spent.
PubKey Script Data: each element pushed onto the the stack by a data-pushing opcode in any pubkey script from this transaction is individually compared to the filter. (If a pubkey script element matches the filter, the filter will be immediately updated if the
BLOOM_UPDATE_ALLflag was set; if the pubkey script is in the P2PKH format and matches the filter, the filter will be immediately updated if theBLOOM_UPDATE_P2PUBKEY_ONLYflag was set. See the subsection below for details.)
As of Dash Core 0.14.0, elements in the extra payload section of DIP2-based special transactions are also compared against bloom filters.
The following annotated hexdump of a transaction is from the raw transaction format section; the elements which would be checked by the filter are emphasized in bold. Note that this transaction’s TXID (01000000017b1eab[...]) would also be checked, and that the outpoint TXID and index number below would be checked as a single 36-byte element.
01000000 ................................... Version
01 ......................................... Number of inputs
|
| 7b1eabe0209b1fe794124575ef807057
| c77ada2138ae4fa8d6c4de0398a14f3f ......... Outpoint TXID
| 00000000 ................................. Outpoint index number
|
| 49 ....................................... Bytes in sig. script: 73
| | 48 ..................................... Push 72 bytes as data
| | | 30450221008949f0cb400094ad2b5eb3
| | | 99d59d01c14d73d8fe6e96df1a7150de
| | | b388ab8935022079656090d7f6bac4c9
| | | a94e0aad311a4268e082a725f8aeae05
| | | 73fb12ff866a5f01 ..................... Secp256k1 signature
|
| ffffffff ................................. Sequence number: UINT32_MAX
01 ......................................... Number of outputs
| f0ca052a01000000 ......................... Satoshis (49.99990000 BTC)
|
| 19 ....................................... Bytes in pubkey script: 25
| | 76 ..................................... OP_DUP
| | a9 ..................................... OP_HASH160
| | 14 ..................................... Push 20 bytes as data
| | | cbc20a7664f2f69e5355aa427045bc15
| | | e7c6c772 ............................. PubKey hash
| | 88 ..................................... OP_EQUALVERIFY
| | ac ..................................... OP_CHECKSIG
00000000 ................................... locktime: 0 (a block height)
Updating A Bloom Filter#
Clients will often want to track inputs that spend outputs (outpoints) relevant to their wallet, so the filterload field nFlags can be set to allow the filtering node to update the filter when a match is found. When the filtering node sees a pubkey script that pays a pubkey, address, or other data element matching the filter, the filtering node immediately updates the filter with the outpoint corresponding to that pubkey script.
If an input later spends that outpoint, the filter will match it, allowing the filtering node to tell the client that one of its transaction outputs has been spent.
The nFlags field has three allowed values:
Value |
Name |
Description |
|---|---|---|
0 |
|
The filtering node should not update the filter. |
1 |
|
If the filter matches any data element in a pubkey script, the corresponding outpoint is added to the filter. |
2 |
|
If the filter matches any data element in a pubkey script and that script is either a P2PKH or non-P2SH pay-to-multisig script, the corresponding outpoint is added to the filter. |
In addition, because the filter size stays the same even though additional elements are being added to it, the false positive rate increases. Each false positive can result in another element being added to the filter, creating a feedback loop that can (after a certain point) make the filter useless. For this reason, clients using automatic filter updates need to monitor the actual false positive rate and send a new filter when the rate gets too high.
getaddr#
The getaddr message requests an addr message from the receiving node, preferably one with lots of IP addresses of other receiving nodes. The transmitting node can use those IP addresses to quickly update its database of available nodes rather than waiting for unsolicited addr messages to arrive over time.
There is no payload in a getaddr message. See the message header section for an example of a message without a payload.
getsporks#
The getsporks message requests spork messages from the receiving node.
There is no payload in a getsporks message. See the message header section for an example of a message without a payload.
ping#
The ping message helps confirm that the receiving peer is still connected. If a TCP/IP error is encountered when sending the ping message (such as a connection timeout), the transmitting node can assume that the receiving node is disconnected. The response to a ping message is the pong message.
Before protocol version 60000, the ping message had no payload. As of protocol version 60001 and all later versions, the message includes a single field, the nonce.
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
8 |
nonce |
uint64_t |
Added in protocol version 60001 as described by BIP31. |
The annotated hexdump below shows a ping message. (The message header has been omitted.)
0094102111e2af4d ... Nonce
pong#
Added in protocol version 60001 as described by BIP31.
The pong message replies to a ping message, proving to the pinging node that the ponging node is still alive. Dash Core will, by default, disconnect from any clients which have not responded to a ping message within 20 minutes.
To allow nodes to keep track of latency, the pong message sends back the same nonce received in the ping message it is replying to.
The format of the pong message is identical to the ping message; only the message header differs.
sendaddrv2#
Added in protocol version 70220 of Dash Core
The sendaddrv2 message signals support for receiving addrv2 messages (defined in BIP155). It also implies that its sender can encode as addrv2 and would send addrv2 messages instead of addr messages to a peer that has signaled addrv2 support by sending a sendaddrv2 message.
There is no payload in a sendaddrv2 message. See the message header section for an example of a message without a payload.
sendcmpct#
Added in protocol version 70209 of Dash Core as described by BIP152
The sendcmpct message tells the receiving peer whether or not to announce new blocks using a cmpctblock message. It also sends the compact block protocol version it supports. The sendcmpct message is defined as a message containing a 1-byte integer followed by a 8-byte integer. The first integer is interpreted as a boolean and should have a value of either 1 or 0. The second integer is be interpreted as a little-endian version number.
Upon receipt of a sendcmpct message with the first and second integers set to 1, the node should announce new blocks by sending a cmpctblock message.
Upon receipt of a sendcmpct message with the first integer set to 0, the node shouldn’t announce new blocks by sending a cmpctblock message, but instead announce new blocks by sending invs or headers, as defined by BIP130.
Upon receipt of a sendcmpct message with the second integer set to something other than 1, nodes should treat the peer as if they had not received the message (as it indicates the peer will provide an unexpected encoding in cmpctblock messages, and/or other, messages). This allows future versions to send duplicate sendcmpct messages with different versions as a part of a version handshake.
Nodes should check for a protocol version of >= 70209 before sending sendcmpct messages. Nodes shouldn’t send a request for a MSG_CMPCT_BLOCK object to a peer before having received a sendcmpct message from that peer. Nodes shouldn’t request a MSG_CMPCT_BLOCK object before having sent all sendcmpct messages to that peer which they intend to send, as the peer cannot know what protocol version to use in the response.
The structure of a sendcmpct message is defined below.
Bytes |
Name |
Data Type |
Description |
|---|---|---|---|
1 |
announce |
bool |
0 - Announce blocks via |
8 |
version |
uint64_t |
The compact block protocol version number |
The annotated hexdump below shows a sendcmpct message. (The message header has been omitted.)
01 ................................. Block announce type: Compact Blocks
0100000000000000 ................... Compact block version: 1
senddsq#
Added in protocol version 70214 of Dash Core
The senddsq message is used to notify a peer whether or not to send dsq messages. This allows clients that are not interested in participating in CoinJoin processing (e.g. mobile wallet) to minimize data usage.
Bytes |
Name |
Data type |
Description |
|---|---|---|---|
1 |
fSendDSQueue |
bool |
0 - Notify peer to not send any |
The following annotated hexdump shows a senddsq message. (The message header has been omitted.)
01 ................................. CoinJoin participation: Enabled (1)
sendheaders#
The sendheaders message tells the receiving peer to send new block announcements using a headers message rather than an inv message.
There is no payload in a sendheaders message. See the message header section for an example of a message without a payload.
sendheaders2#
Added in protocol version 70223 of Dash Core.
The sendheaders2 message tells the receiving peer to send new block announcements using a headers2 message rather than an inv message.
There is no payload in a sendheaders2 message. See the message header section for an example of a message without a payload.
spork#
Sporks are a mechanism by which updated code is released to the network, but not immediately made active (or “enforced”). Enforcement of the updated code can be activated remotely. Should problems arise, the code can be deactivated in the same manner, without the need for a network-wide rollback or client update.
A spork message may be sent in response to a getsporks message.
The spork message tells the receiving peer the status of the spork defined by the SporkID field. Upon receiving a spork message, the client must verify the signature before accepting the spork message as valid.
Bytes |
Name |
Data type |
Required |
Description |
|---|---|---|---|---|
4 |
nSporkID |
int |
Required |
ID assigned in spork.h |
8 |
nValue |
int64_t |
Required |
Value assigned to spork |
8 |
nTimeSigned |
int64_t |
Required |
Time the spork value was signed |
66 |
vchSig |
char[] |
Required |
Length (1 byte) + Signature (65 bytes) |
The following annotated hexdump shows a spork message.
11270000 .................................... Spork ID: Spork 2 InstantSend enabled (10001)
0000000000000000 ............................ Value (0)
2478da5900000000 ............................ Epoch time: 2017-10-08 19:10:28 UTC (1507489828)
41 .......................................... Signature length: 65
1b6762d3e70890b5cfaed5d1fd72121c
d32020c827a89f8128a00acd210f4ea4
1b36c26c3767f8a24f48663e189865ed
403ed1e850cdb4207cdd466419d9d183
45 .......................................... Masternode Signature
Active sporks#
The list of all active sporks can be found in
src/spork.h. See the removed
sporks section for a list of previously removed sporks.
Spork ID |
Num. |
Name |
Description |
|---|---|---|---|
10001 |
2 |
|
Updated in Dash Core 0.17.0 |
10002 |
3 |
|
Turns on and off InstantSend block filtering |
10008 |
9 |
|
Superblocks are enabled (20% of the block subsidy is allocated to the Dash treasury for funding approved proposals) |
10016 |
17 |
|
Enable long-living masternode quorum (LLMQ) distributed key generation (DKG). When enabled, simple PoSe scoring and banning is active as well. |
10018 |
19 |
|
Updated in Dash Core 19.2.0 |
10020 |
21 |
|
Added in Dash Core 0.16.0 |
10022 |
23 |
|
Added in Dash Core 0.17.0 |
10023 |
24 |
|
Added in Dash Core 20.0.0 (Testnet/Devnet/Regtest only) |
Spork 2 values
As of Dash Core 0.17.0, spork 2 supports two different enabled values:
0- Masternodes create InstantSend locks for all transactions.1- Masternodes only create InstantSend locks for transactions included in a block. Transactions in the mempool are not locked.
Mode 1 is only for use in the event of a sustained overload of InstantSend to ensure that ChainLocks can remain operational. See PR 4024 for details.
Spork 19 values
As of Dash Core 19.2.0, spork 19 supports two different enable values:
0- Masternodes create ChainLocks for all blocks.1- Masternodes retain existing ChainLocks, but do not sign new ones.
See PR 5398 for implementation details.
Spork 21 and 23 values
Spork 21 and 23 support two different enabled values:
0- The spork is active for all quorums regardless of quorum size.1- The spork is active only for quorums which have a member size less than 100.
Removed sporks#
The following sporks were used in the past but are no longer necessary and have been removed recently. To see sporks removed longer ago, please see the previous version of documentation.
Note that spork 6 was never enabled on mainnet and was removed in Dash Core 0.16.0. The associated logic was hardened in PR 3662 to support testnet (where it is enabled). If testnet is reset at some point in the future, the remaining logic will be removed.
Spork ID |
Num. |
Name |
Description |
|---|---|---|---|
10005 |
6 |
|
Removed in Dash Core 0.16.0. |
10014 |
15 |
|
Removed in Dash Core 0.16.0. |
10015 |
16 |
|
Removed in Dash Core 0.16.0. |
10019 |
20 |
|
Removed in Dash Core 0.16.0. |
10021 |
22 |
|
Removed in Dash Core 0.17.0 |
Spork verification#
To verify vchSig, compare the hard-coded spork public key (strSporkPubKey from src/chainparams.cpp) with the public key recovered from the spork message’s hash and vchSig value (implementation details for Dash Core can be found in CPubKey::RecoverCompact). The hash is a double SHA-256 hash of:
The spork magic message (
"DarkCoin Signed Message:\n")nSporkID + nValue + nTimeSigned
Network |
Spork Pubkey (wrapped) |
|---|---|
Mainnet |
04549ac134f694c0243f503e8c8a9a986f5de6610049c40b07816809b0d1 |
Testnet3 |
046f78dcf911fbd61910136f7f0f8d90578f68d0b3ac973b5040fb7afb50 |
RegTest |
Undefined |
Devnets |
046f78dcf911fbd61910136f7f0f8d90578f68d0b3ac973b5040fb7afb50 |
verack#
The verack message acknowledges a previously-received version message, informing the connecting node that it can begin to send other messages. The verack message has no payload; for an example of a message with no payload, see the message headers section.
version#
The version message provides information about the transmitting node to the receiving node at the beginning of a connection. Until both peers have exchanged version messages, no other messages will be accepted.
If a version message is accepted, the receiving node should send a verack message—but no node should send a verack message before initializing its half of the connection by first sending a version message.
Protocol version 70214 added a masternode authentication (challenge/response) system. Following the verack message, masternodes should send a mnauth message that signs the mnauth_challenge with their BLS operator key.
Bytes |
Name |
Data |
Required/ |
Description |
|---|---|---|---|---|
4 |
version |
int32_t |
Required |
The highest protocol version understood by the transmitting node. See the protocol version section. |
8 |
services |
uint64_t |
Required |
The services supported by the transmitting node encoded as a bitfield. See the list of service codes below. |
8 |
timestamp |
int64_t |
Required |
The current Unix epoch time according to the transmitting node’s clock. Because nodes will reject blocks with timestamps more than two hours in the future, this field can help other nodes to determine that their clock is wrong. |
8 |
addr_recv services |
uint64_t |
Required |
Added in protocol version 106. |
16 |
addr_recv IP address |
char |
Required |
Added in protocol version 106. |
2 |
addr_recv port |
uint16_t |
Required |
Added in protocol version 106. |
8 |
addr_trans services |
uint64_t |
Required |
The services supported by the transmitting node. Should be identical to the ‘services’ field above. |
16 |
addr_trans IP address |
char |
Required |
The IPv6 address of the transmitting node in big endian byte order. IPv4 addresses can be provided as IPv4-mapped IPv6 addresses. Set to ::ffff:127.0.0.1 if unknown. |
2 |
addr_trans port |
uint16_t |
Required |
The port number of the transmitting node in big endian byte order. |
8 |
nonce |
uint64_t |
Required |
A random nonce which can help a node detect a connection to itself. If the nonce is 0, the nonce field is ignored. If the nonce is anything else, a node should terminate the connection on receipt of a |
Varies |
user_agent bytes |
compactSize uint |
Required |
Number of bytes in following user_agent field. If 0x00, no user agent field is sent. |
Varies |
user_agent |
string |
Required if user_agent bytes > 0 |
Renamed in protocol version 60000. |
4 |
start_height |
int32_t |
Required |
The height of the transmitting node’s best block chain or, in the case of an SPV client, best block header chain. |
1 |
relay |
bool |
Optional |
Added in protocol version 70001 as described by BIP37. |
32 |
mnauth_ |
uint256 |
Optional |
Added in protocol version 70214 |
1 |
mn_connection |
bool |
Optional |
If 0x00, the connection is from a non-masternode. If 0x01, the connection is from a masternode. |
The following service identifiers have been assigned.
Value |
Name |
Description |
|---|---|---|
0x00 |
Unnamed |
This node is not a full node. It may not be able to provide any data except for the transactions it originates. |
0x01 |
|
This is a full node and can be asked for full blocks. It should implement all protocol features available in its self-reported protocol version. |
0x02 |
|
Removed in Dash Core 20.0.0 |
0x04 |
|
This node is capable and willing to handle bloom-filtered connections. Dash Core nodes used to support this by default, without advertising this bit, but no longer do as of protocol version 70201 (= NO_BLOOM_VERSION) |
0x08 |
|
Dash Core does not support this service |
0x40 |
|
This node supports basic block filter requests. See BIP157 and BIP158 for details on how this is implemented. |
0x400 |
|
This is the same as |
The following annotated hexdump shows a version message. (The message header has been omitted and the actual IP addresses have been replaced with RFC5737 reserved IP addresses.)
46120100 .................................... Protocol version: 70214
0500000000000000 ............................ Services: NODE_NETWORK (1) + NODE_BLOOM (4)
9c10ad5c00000000 ............................ Epoch time: 1554845852
0100000000000000 ............................ Receiving node's services
00000000000000000000ffffc61b6409 ............ Receiving node's IPv6 address
270f ........................................ Receiving node's port number
0500000000000000 ............................ Transmitting node's services
00000000000000000000ffffcb0071c0 ............ Transmitting node's IPv6 address
270f ........................................ Transmitting node's port number
128035cbc97953f8 ............................ Nonce
12 .......................................... Bytes in user agent string: 18
2f4461736820436f72653a302e31322e312e352f..... User agent: /Dash Core:0.14.0/
851f0b00 .................................... Start height: 76944
01 .......................................... Relay flag: true
5dbb5d1baade6a9afa34db708f72c0dd
b5bd82b3656493484556689640a91357 ............ Masternode Auth. Challenge
00 .......................................... Masternode connection (false)