Bitcoin
How does Bitcoin Core handle service flag spoofing?
There are five service flags in src/protocol.cpp:
static std::string serviceFlagToStr(size_t bit)
{
const uint64_t service_flag = 1ULL << bit;
switch ((ServiceFlags)service_flag)
case NODE_NONE: abort(); // impossible
case NODE_NETWORK: return "NETWORK";
case NODE_BLOOM: return "BLOOM";
case NODE_WITNESS: return "WITNESS";
case NODE_COMPACT_FILTERS: return "COMPACT_FILTERS";
case NODE_NETWORK_LIMITED: return "NETWORK_LIMITED";
// Not using default, so we get warned when a case is missing
/** nServices flags */
enum ServiceFlags : uint64_t {
// NOTE: When adding here, be sure to update serviceFlagToStr too
// Nothing
NODE_NONE = 0,
// NODE_NETWORK means that the node is capable of serving the complete block chain. It is currently
// set by all Bitcoin Core non pruned nodes, and is unset by SPV clients or other light clients.
NODE_NETWORK = (1 << 0),
// NODE_BLOOM means the node is capable and willing to handle bloom-filtered connections.
// Bitcoin Core nodes used to support this by default, without advertising this bit,
// but no longer do as of protocol version 70011 (= NO_BLOOM_VERSION)
NODE_BLOOM = (1 << 2),
// NODE_WITNESS indicates that a node can be asked for blocks and transactions including
// witness data.
NODE_WITNESS = (1 << 3),
// NODE_COMPACT_FILTERS means the node will service basic block filter requests.
// See BIP157 and BIP158 for details on how this is implemented.
NODE_COMPACT_FILTERS = (1 << 6),
// NODE_NETWORK_LIMITED means the same as NODE_NETWORK with the limitation of only
// serving the last 288 (2 day) blocks
// See BIP159 for details on how this is implemented.
NODE_NETWORK_LIMITED = (1 << 10),
Do Bitcoin Core nodes check if peers are bluffing about service flags? Example: peer NODE_NETWORK
A node that has its flag set but has been cleaned up.