diff --git a/Makefile b/Makefile
index 3bbd7f74..71063810 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ dnsseed: dns.o bitcoin.o netbase.o protocol.o db.o main.o util.o
 	g++ -pthread $(LDFLAGS) -o dnsseed dns.o bitcoin.o netbase.o protocol.o db.o main.o util.o -lcrypto
 
 %.o: %.cpp bitcoin.h netbase.h protocol.h db.h serialize.h uint256.h util.h
-	g++ -DUSE_IPV6 -pthread $(CXXFLAGS) -Wno-invalid-offsetof -c -o $@ $<
+	g++ -pthread $(CXXFLAGS) -Wno-invalid-offsetof -c -o $@ $<
 
 dns.o: dns.c
 	gcc -pthread -std=c99 $(CXXFLAGS) dns.c -c -o dns.o
diff --git a/main.cpp b/main.cpp
index 2e88ed45..2e0e187c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -188,14 +188,12 @@ class CDnsThread {
           memcpy(&a.data.v4, &addr, 4);
           cache.push_back(a);
           nIPv4++;
-#ifdef USE_IPV6
         } else if ((*it).GetIn6Addr(&addr6)) {
           addr_t a;
           a.v = 6;
           memcpy(&a.data.v6, &addr6, 16);
           cache.push_back(a);
           nIPv6++;
-#endif
         }
       }
       cacheHits = 0;
diff --git a/netbase.cpp b/netbase.cpp
index 2630f87b..449e635f 100644
--- a/netbase.cpp
+++ b/netbase.cpp
@@ -74,18 +74,10 @@ bool static LookupIntern(const char *pszName, std::vector<CNetAddr>& vIP, unsign
     aiHint.ai_socktype = SOCK_STREAM;
     aiHint.ai_protocol = IPPROTO_TCP;
 #ifdef WIN32
-#  ifdef USE_IPV6
     aiHint.ai_family = AF_UNSPEC;
-#  else
-    aiHint.ai_family = AF_INET;
-#  endif
     aiHint.ai_flags = fAllowLookup ? 0 : AI_NUMERICHOST;
 #else
-#  ifdef USE_IPV6
     aiHint.ai_family = AF_UNSPEC;
-#  else
-    aiHint.ai_family = AF_INET;
-#  endif
     aiHint.ai_flags = fAllowLookup ? AI_ADDRCONFIG : AI_NUMERICHOST;
 #endif
     struct addrinfo *aiRes = NULL;
@@ -102,13 +94,11 @@ bool static LookupIntern(const char *pszName, std::vector<CNetAddr>& vIP, unsign
             vIP.push_back(CNetAddr(((struct sockaddr_in*)(aiTrav->ai_addr))->sin_addr));
         }
 
-#ifdef USE_IPV6
         if (aiTrav->ai_family == AF_INET6)
         {
             assert(aiTrav->ai_addrlen >= sizeof(sockaddr_in6));
             vIP.push_back(CNetAddr(((struct sockaddr_in6*)(aiTrav->ai_addr))->sin6_addr));
         }
-#endif
 
         aiTrav = aiTrav->ai_next;
     }
@@ -323,11 +313,7 @@ bool static ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRe
 {
     hSocketRet = INVALID_SOCKET;
 
-#ifdef USE_IPV6
     struct sockaddr_storage sockaddr;
-#else
-    struct sockaddr sockaddr;
-#endif
     socklen_t len = sizeof(sockaddr);
     if (!addrConnect.GetSockAddr((struct sockaddr*)&sockaddr, &len)) {
         printf("Cannot connect to %s: unsupported network\n", addrConnect.ToString().c_str());
@@ -578,12 +564,10 @@ CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
     memcpy(ip+12, &ipv4Addr, 4);
 }
 
-#ifdef USE_IPV6
 CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr)
 {
     memcpy(ip, &ipv6Addr, 16);
 }
-#endif
 
 CNetAddr::CNetAddr(const char *pszIp, bool fAllowLookup)
 {
@@ -767,11 +751,7 @@ std::string CNetAddr::ToStringIP() const
     if (IsI2P())
         return EncodeBase32(&ip[6], 10) + ".oc.b32.i2p";
     CService serv(*this, 0);
-#ifdef USE_IPV6
     struct sockaddr_storage sockaddr;
-#else
-    struct sockaddr sockaddr;
-#endif
     socklen_t socklen = sizeof(sockaddr);
     if (serv.GetSockAddr((struct sockaddr*)&sockaddr, &socklen)) {
         char name[1025] = "";
@@ -816,13 +796,11 @@ bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
     return true;
 }
 
-#ifdef USE_IPV6
 bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
 {
     memcpy(pipv6Addr, ip, 16);
     return true;
 }
-#endif
 
 // get canonical identifier of an address' group
 // no two connections will be attempted to addresses with the same group
@@ -1008,23 +986,19 @@ CService::CService(const struct in_addr& ipv4Addr, unsigned short portIn) : CNet
 {
 }
 
-#ifdef USE_IPV6
 CService::CService(const struct in6_addr& ipv6Addr, unsigned short portIn) : CNetAddr(ipv6Addr), port(portIn)
 {
 }
-#endif
 
 CService::CService(const struct sockaddr_in& addr) : CNetAddr(addr.sin_addr), port(ntohs(addr.sin_port))
 {
     assert(addr.sin_family == AF_INET);
 }
 
-#ifdef USE_IPV6
 CService::CService(const struct sockaddr_in6 &addr) : CNetAddr(addr.sin6_addr), port(ntohs(addr.sin6_port))
 {
    assert(addr.sin6_family == AF_INET6);
 }
-#endif
 
 bool CService::SetSockAddr(const struct sockaddr *paddr)
 {
@@ -1032,11 +1006,9 @@ bool CService::SetSockAddr(const struct sockaddr *paddr)
     case AF_INET:
         *this = CService(*(const struct sockaddr_in*)paddr);
         return true;
-#ifdef USE_IPV6
     case AF_INET6:
         *this = CService(*(const struct sockaddr_in6*)paddr);
         return true;
-#endif
     default:
         return false;
     }
@@ -1108,7 +1080,6 @@ bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
         paddrin->sin_port = htons(port);
         return true;
     }
-#ifdef USE_IPV6
     if (IsIPv6()) {
         if (*addrlen < (socklen_t)sizeof(struct sockaddr_in6))
             return false;
@@ -1121,7 +1092,6 @@ bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
         paddrin6->sin6_port = htons(port);
         return true;
     }
-#endif
     return false;
 }
 
diff --git a/netbase.h b/netbase.h
index 560e2182..6fbf881f 100644
--- a/netbase.h
+++ b/netbase.h
@@ -73,10 +73,8 @@ class CNetAddr
         int GetReachabilityFrom(const CNetAddr *paddrPartner = NULL) const;
         void print() const;
 
-#ifdef USE_IPV6
         CNetAddr(const struct in6_addr& pipv6Addr);
         bool GetIn6Addr(struct in6_addr* pipv6Addr) const;
-#endif
 
         friend bool operator==(const CNetAddr& a, const CNetAddr& b);
         friend bool operator!=(const CNetAddr& a, const CNetAddr& b);
@@ -117,10 +115,8 @@ class CService : public CNetAddr
         std::string ToStringIPPort() const;
         void print() const;
 
-#ifdef USE_IPV6
         CService(const struct in6_addr& ipv6Addr, unsigned short port);
         CService(const struct sockaddr_in6& addr);
-#endif
 
         IMPLEMENT_SERIALIZE
             (