diff --git a/src/chainparamsbase.cpp b/src/chainparamsbase.cpp
index 09cfbf140..4edd88377 100644
--- a/src/chainparamsbase.cpp
+++ b/src/chainparamsbase.cpp
@@ -1,62 +1,66 @@
 // Copyright (c) 2010 Satoshi Nakamoto
 // Copyright (c) 2009-2015 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <chainparamsbase.h>
 
 #include <tinyformat.h>
 #include <util/system.h>
 
 #include <cassert>
 
 const std::string CBaseChainParams::MAIN = "main";
 const std::string CBaseChainParams::TESTNET = "test";
 const std::string CBaseChainParams::REGTEST = "regtest";
 
 void SetupChainParamsBaseOptions(ArgsManager &argsman) {
     argsman.AddArg(
         "-chain=<chain>",
         "Use the chain <chain> (default: main). Allowed values: main, "
         "test, regtest",
         ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg(
         "-regtest",
         "Enter regression test mode, which uses a special chain in which "
         "blocks can be solved instantly. This is intended for regression "
         "testing tools and app development. Equivalent to -chain=regtest.",
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-testnet", "Use the test chain. Equivalent to -chain=test.",
                    ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
 }
 
 static std::unique_ptr<CBaseChainParams> globalChainBaseParams;
 
 const CBaseChainParams &BaseParams() {
     assert(globalChainBaseParams);
     return *globalChainBaseParams;
 }
 
+/**
+ * Port numbers for incoming Tor connections (8334, 18334, 38334, 18445) have
+ * been chosen arbitrarily to keep ranges of used ports tight.
+ */
 std::unique_ptr<CBaseChainParams>
 CreateBaseChainParams(const std::string &chain) {
     if (chain == CBaseChainParams::MAIN) {
-        return std::make_unique<CBaseChainParams>("", 8332);
+        return std::make_unique<CBaseChainParams>("", 8332, 8334);
     }
 
     if (chain == CBaseChainParams::TESTNET) {
-        return std::make_unique<CBaseChainParams>("testnet3", 18332);
+        return std::make_unique<CBaseChainParams>("testnet3", 18332, 18334);
     }
 
     if (chain == CBaseChainParams::REGTEST) {
-        return std::make_unique<CBaseChainParams>("regtest", 18443);
+        return std::make_unique<CBaseChainParams>("regtest", 18443, 18445);
     }
 
     throw std::runtime_error(
         strprintf("%s: Unknown chain %s.", __func__, chain));
 }
 
 void SelectBaseParams(const std::string &chain) {
     globalChainBaseParams = CreateBaseChainParams(chain);
     gArgs.SelectConfigNetwork(chain);
 }
diff --git a/src/chainparamsbase.h b/src/chainparamsbase.h
index ff0e1c313..aff0e24e6 100644
--- a/src/chainparamsbase.h
+++ b/src/chainparamsbase.h
@@ -1,59 +1,66 @@
 // Copyright (c) 2014-2015 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_CHAINPARAMSBASE_H
 #define BITCOIN_CHAINPARAMSBASE_H
 
 #include <memory>
 #include <string>
 
 class ArgsManager;
 
 /**
  * CBaseChainParams defines the base parameters
  * (shared between bitcoin-cli and bitcoind)
  * of a given instance of the Bitcoin system.
  */
 class CBaseChainParams {
 public:
     /** BIP70 chain name strings (main, test or regtest) */
     static const std::string MAIN;
     static const std::string TESTNET;
     static const std::string REGTEST;
 
     const std::string &DataDir() const { return strDataDir; }
     int RPCPort() const { return nRPCPort; }
+    uint16_t OnionServiceTargetPort() const {
+        return m_onion_service_target_port;
+    }
 
     CBaseChainParams() = delete;
-    CBaseChainParams(const std::string &data_dir, int rpc_port)
-        : nRPCPort(rpc_port), strDataDir(data_dir) {}
+    CBaseChainParams(const std::string &data_dir, int rpc_port,
+                     uint16_t onion_service_target_port)
+        : nRPCPort(rpc_port),
+          m_onion_service_target_port(onion_service_target_port),
+          strDataDir(data_dir) {}
 
 private:
     int nRPCPort;
+    const uint16_t m_onion_service_target_port;
     std::string strDataDir;
 };
 
 /**
  * Creates and returns a std::unique_ptr<CBaseChainParams> of the chosen chain.
  * @returns a CBaseChainParams* of the chosen chain.
  * @throws a std::runtime_error if the chain is not supported.
  */
 std::unique_ptr<CBaseChainParams>
 CreateBaseChainParams(const std::string &chain);
 
 /**
  * Set the arguments for chainparams.
  */
 void SetupChainParamsBaseOptions(ArgsManager &argsman);
 
 /**
  * Return the currently selected parameters. This won't change after app
  * startup, except for unit tests.
  */
 const CBaseChainParams &BaseParams();
 
 /** Sets the params returned by Params() to those for the given network. */
 void SelectBaseParams(const std::string &chain);
 
 #endif // BITCOIN_CHAINPARAMSBASE_H