Inside Bitcoin
Opening the selected file…
Inside Bitcoin
Opening the selected file…
The code behind the network, with room to understand it.
Release published 2026-10-28 · Snapshot fetched 2026-11-01. Latest stable release at fetch time; development branches and Git history are excluded. Only the selected code window and visible folders load here.
251connections to that address and port as incoming Tor connections252(default: 127.0.0.1:8334=onion, testnet3: 127.0.0.1:18334=onion,253testnet4: 127.0.0.1:48334=onion, signet: 127.0.0.1:38334=onion,254regtest: 127.0.0.1:18445=onion)255.HP256\fB\-cjdnsreachable\fR257.IP258If set, then this host is configured for CJDNS (connecting to fc00::/8259addresses would lead us to the CJDNS network, see doc/cjdns.md)260(default: 0)261.HP262\fB\-connect=\fR<ip>263.IP264Connect only to the specified node; \fB\-noconnect\fR disables automatic265connections (the rules for this peer are the same as for266\fB\-addnode\fR). This option can be specified multiple times to connect267to multiple nodes.268.HP269\fB\-discover\fR270.IP271Discover own IP addresses (default: 1 when listening and no \fB\-externalip\fR272or \fB\-proxy\fR)273.HP274\fB\-dns\fR275.IP276Allow DNS lookups for \fB\-addnode\fR, \fB\-seednode\fR and \fB\-connect\fR (default: 1)277.HP278\fB\-dnsseed\fR279.IP280Query for peer addresses via DNS lookup, if low on addresses (default: 1281unless \fB\-connect\fR used or \fB\-maxconnections\fR=\fI\,0\/\fR)282.HP283\fB\-externalip=\fR<ip>284.IP285Specify your own public address286.HP287\fB\-fixedseeds\fR288.IP289Allow fixed seeds if DNS seeds don't provide peers (default: 1)290.HP291\fB\-forcednsseed\fR292.IP293Always query for peer addresses via DNS lookup (default: 0)294.HP295\fB\-i2pacceptincoming\fR296.IP297Whether to accept inbound I2P connections (default: 1). Ignored if298\fB\-i2psam\fR is not set. Listening for inbound I2P connections is done299through the SAM proxy, not by binding to a local address and300port.301.HP302\fB\-i2psam=\fR<ip:port>303.IP304I2P SAM proxy to reach I2P peers and accept I2P connections305.HP306\fB\-inboundrelaypercent=\fR<n>307.IP308Permit a maximum percent of inbound connections to relay transactions,309to limit memory utilization (0 to 100, default: 50).310.HP311\fB\-listen\fR312.IP313Accept connections from outside (default: 1 if no \fB\-proxy\fR, \fB\-connect\fR or314\fB\-maxconnections\fR=\fI\,0\/\fR)315.HP316\fB\-listenonion\fR317.IP318Automatically create Tor onion service (default: 1)319.HP320\fB\-maxconnections=\fR<n>321.IP322Maintain at most <n> automatic connections to peers (default: 200,323maximum: 2000). 11 slots of these are reserved for outgoing324connections. See \fB\-inboundrelaypercent\fR for more information about325limits applied to transaction relay inbound peers. This limit326does not apply to connections manually added via \fB\-addnode\fR or the327addnode RPC, which have a separate limit of 8. It does not apply328to short\-lived private broadcast connections either, which have a329separate limit of 64.330.HP331\fB\-maxreceivebuffer=\fR<n>332.IP333Maximum per\-connection receive buffer, <n>*1000 bytes (default: 5000)334.HP335\fB\-maxsendbuffer=\fR<n>336.IP337Maximum per\-connection memory usage for the send buffer, <n>*1000 bytes338(default: 1000)339.HP340\fB\-maxuploadtarget=\fR<n>341.IP342Tries to keep outbound traffic under the given target per 24h. Limit343does not apply to peers with 'download' permission or blocks344created within past week. 0 = no limit (default: 0M). Optional345suffix units [k|K|m|M|g|G|t|T] (default: M). Lowercase is 1000346base while uppercase is 1024 base347.HP348\fB\-natpmp\fR349.IP350Use PCP or NAT\-PMP to map the listening port (default: 1)351.HP352\fB\-networkactive\fR353.IP354Enable all P2P network activity (default: 1). Can be changed by the355setnetworkactive RPC command356.HP357\fB\-onion=\fR<ip:port|path>358.IP359Use separate SOCKS5 proxy to reach peers via Tor onion services, set360\fB\-noonion\fR to disable (default: \fB\-proxy\fR). May be a local file path361prefixed with 'unix:'.362.HP363\fB\-onlynet=\fR<net>364.IP365Make automatic outbound connections only to network <net> (ipv4, ipv6,366onion, i2p, cjdns). Inbound and manual connections are not367affected by this option. It can be specified multiple times to368allow multiple networks.369.HP370\fB\-peerblockfilters\fR371.IP372Serve compact block filters to peers per BIP 157 (default: 0)373.HP374\fB\-peerbloomfilters\fR375.IP376Support filtering of blocks and transaction with bloom filters (default:3770)378.HP379\fB\-port=\fR<port>380.IP381Listen for connections on <port> (default: 8333, testnet3: 18333,382testnet4: 48333, signet: 38333, regtest: 18444). Not relevant for383I2P (see doc/i2p.md). If set to a value x, the default onion384listening port will be set to x+1.385.HP386\fB\-proxy=\fR<ip>[:<port>]|unix:<path>[=<network>]387.IP388Connect through SOCKS5 proxy, set \fB\-noproxy\fR to disable. May be a local389file path prefixed with 'unix:' if the proxy supports it. Could390end in =network to set the proxy only for that network. The391network can be any of ipv4, ipv6, onion, cjdns. (default:392disabled)393.HP394\fB\-proxyrandomize\fR395.IP396Randomize credentials for every proxy connection. This enables Tor397stream isolation (default: 1)398.HP399\fB\-seednode=\fR<ip>400.IP401Connect to a node to retrieve peer addresses, and disconnect. This402option can be specified multiple times to connect to multiple403nodes. During startup, seednodes will be tried before dnsseeds.404.HP405\fB\-timeout=\fR<n>406.IP407Specify socket connection timeout in milliseconds. If an initial attempt408to connect is unsuccessful after this amount of time, drop it409(minimum: 1, default: 5000)410.HP411\fB\-torcontrol=\fR<ip>:<port>412.IP413Tor control host and port to use if onion listening enabled (default:414127.0.0.1:9051). If no port is specified, the default port of4159051 will be used.416.HP417\fB\-torpassword=\fR<pass>418.IP419Tor control port password (default: empty)420.HP421\fB\-v2transport\fR422.IP423Support v2 transport (default: 1)424.HP425\fB\-whitebind=\fR<[permissions@]addr>426.IP427Bind to the given address and add permission flags to the peers428connecting to it. Use [host]:port notation for IPv6. Allowed429permissions: bloomfilter (allow requesting BIP37 filtered blocks430and transactions), noban (do not ban for misbehavior; implies431download), forcerelay (relay transactions that are already in the432mempool; implies relay), relay (relay even in \fB\-blocksonly\fR mode,433and unlimited transaction announcements), mempool (allow434requesting BIP35 mempool contents), download (allow getheaders435during IBD, no disconnect after maxuploadtarget limit), addr436(responses to GETADDR avoid hitting the cache and contain random437records with the most up\-to\-date info). Specify multiple438permissions separated by commas (default:439download,noban,mempool,relay). Can be specified multiple times.440.HP441\fB\-whitelist=\fR<[permissions@]IP address or network>442.IP443Add permission flags to the peers using the given IP address (e.g.4441.2.3.4) or CIDR\-notated network (e.g. 1.2.3.0/24). Uses the same445permissions as \fB\-whitebind\fR. Additional flags "in" and "out"446control whether permissions apply to incoming connections and/or447manual (default: incoming only). Can be specified multiple times.448.PP449Wallet options:450.HP451\fB\-addresstype\fR452.IP453What type of addresses to use ("legacy", "p2sh\-segwit", "bech32",454"bech32m", default: "bech32")455.HP456\fB\-avoidpartialspends\fR457.IP458Group outputs by address, selecting many (possibly all) or none, instead459of selecting on a per\-output basis. Privacy is improved as460addresses are mostly swept with fewer transactions and outputs461are aggregated in clean change addresses. It may result in higher462fees due to less optimal coin selection caused by this added463limitation and possibly a larger\-than\-necessary number of inputs464being used. Always enabled for wallets with "avoid_reuse"465enabled, otherwise default: 0.466.HP467\fB\-changetype\fR468.IP469What type of change to use ("legacy", "p2sh\-segwit", "bech32",470"bech32m"). Default is "legacy" when \fB\-addresstype\fR=\fI\,legacy\/\fR, else it471is an implementation detail.472.HP473\fB\-consolidatefeerate=\fR<amt>474.IP475The maximum feerate (in BTC/kvB) at which transaction building may use476more inputs than strictly necessary so that the wallet's UTXO477pool can be reduced (default: 0.0001).478.HP479\fB\-disablewallet\fR480.IP481Do not load the wallet and disable wallet RPC calls482.HP483\fB\-discardfee=\fR<amt>484.IP485The fee rate (in BTC/kvB) that indicates your tolerance for discarding486change by adding it to the fee (default: 0.0001). Note: An output487is discarded if it is dust at this rate, but we will always488discard up to the dust relay fee and a discard fee above that is489limited by the fee estimate for the longest target490.HP491\fB\-fallbackfee=\fR<amt>492.IP493A fee rate (in BTC/kvB) that will be used when fee estimation has494insufficient data. 0 to entirely disable the fallbackfee feature.495(default: 0.00)496.HP497\fB\-keypool=\fR<n>498.IP499Set key pool size to <n> (default: 1000). Warning: Smaller sizes may500increase the risk of losing funds when restoring from an old
Independent explanations by MyBitcoinExplorer. Not affiliated with or endorsed by Bitcoin Core. Guides are educational and do not replace the source or its tests.
Bitcoin Core source © its contributors, distributed under the MIT license. Original notices and bundled third-party licenses are retained in the source tree.