diff --git a/src/Cedar/Cedar.c b/src/Cedar/Cedar.c
index 04d0556b..c00e0c58 100644
--- a/src/Cedar/Cedar.c
+++ b/src/Cedar/Cedar.c
@@ -1765,6 +1765,8 @@ CEDAR *NewCedar(X *server_x, K *server_k)
 
 	c->UdpPortList = NewIntList(false);
 
+	c->DhParamBits = DH_PARAM_BITS_DEFAULT;
+
 	InitNetSvcList(c);
 
 	InitLocalBridgeList(c);
diff --git a/src/Cedar/Cedar.h b/src/Cedar/Cedar.h
index bc15b32f..39570cd9 100644
--- a/src/Cedar/Cedar.h
+++ b/src/Cedar/Cedar.h
@@ -308,6 +308,7 @@
 #define	FARM_BASE_POINT				100000		// Reference value of the cluster score
 #define	FARM_DEFAULT_WEIGHT			100			// Standard performance ratio
 
+#define DH_PARAM_BITS_DEFAULT		2048		// Bits of Diffie-Hellman Parameters
 
 
 #define	SE_UDP_SIGN			"SE2P"		// Not used (only old UDP mode)
@@ -1053,6 +1054,7 @@ typedef struct CEDAR
 	LOCK *FifoBudgetLock;			// Fifo budget lock
 	UINT FifoBudget;				// Fifo budget
 	SSL_ACCEPT_SETTINGS SslAcceptSettings;	// SSL Accept Settings
+	UINT DhParamBits;  // Bits of Diffie-Hellman parameters
 	char OpenVPNDefaultClientOption[MAX_SIZE];	// OpenVPN Default Client Option String
 } CEDAR;
 
diff --git a/src/Cedar/Interop_OpenVPN.c b/src/Cedar/Interop_OpenVPN.c
index aecac52e..5d3f379d 100644
--- a/src/Cedar/Interop_OpenVPN.c
+++ b/src/Cedar/Interop_OpenVPN.c
@@ -2595,7 +2595,7 @@ OPENVPN_SERVER *NewOpenVpnServer(CEDAR *cedar, INTERRUPT_MANAGER *interrupt, SOC
 
 	OvsLog(s, NULL, NULL, "LO_START");
 
-	s->Dh = DhNewGroup2();
+	s->Dh = DhNewFromBits(DH_PARAM_BITS_DEFAULT);
 
 	return s;
 }
@@ -2703,6 +2703,21 @@ OPENVPN_SERVER_UDP *NewOpenVpnServerUdp(CEDAR *cedar)
 	return u;
 }
 
+void OpenVpnServerUdpSetDhParam(OPENVPN_SERVER_UDP *u, DH_CTX *dh)
+{
+	// Validate arguments
+	if (u == NULL) {
+		return;
+	}
+
+	if (u->OpenVpnServer->Dh)
+	{
+		DhFree(u->OpenVpnServer->Dh);
+	}
+
+	u->OpenVpnServer->Dh = dh;
+}
+
 // Apply the port list to the OpenVPN server
 void OvsApplyUdpPortList(OPENVPN_SERVER_UDP *u, char *port_list, IP *listen_ip)
 {
diff --git a/src/Cedar/Interop_OpenVPN.h b/src/Cedar/Interop_OpenVPN.h
index f4320104..a7cd6c1a 100644
--- a/src/Cedar/Interop_OpenVPN.h
+++ b/src/Cedar/Interop_OpenVPN.h
@@ -384,6 +384,8 @@ bool OvsGetNoOpenVpnTcp();
 
 void OvsSetNoOpenVpnUdp(bool b);
 
+void OpenVpnServerUdpSetDhParam(OPENVPN_SERVER_UDP *u, DH_CTX *dh);
+
 
 
 #endif	// INTEROP_OPENVPN_H
diff --git a/src/Cedar/Server.c b/src/Cedar/Server.c
index 5ac3e3e7..e3e6921e 100644
--- a/src/Cedar/Server.c
+++ b/src/Cedar/Server.c
@@ -6186,6 +6186,18 @@ void SiLoadServerCfg(SERVER *s, FOLDER *f)
 		c->SslAcceptSettings.Tls_Disable1_2 = CfgGetBool(f, "Tls_Disable1_2");
 
 		s->StrictSyslogDatetimeFormat = CfgGetBool(f, "StrictSyslogDatetimeFormat");
+                // Bits of Diffie-Hellman parameters
+		c->DhParamBits = CfgGetInt(f, "DhParamBits");
+		if (c->DhParamBits == 0)
+		{
+			c->DhParamBits = DH_PARAM_BITS_DEFAULT;
+		}
+
+		SetDhParam(DhNewFromBits(c->DhParamBits));
+		if (s->OpenVpnServerUdp)
+		{
+			OpenVpnServerUdpSetDhParam(s->OpenVpnServerUdp, DhNewFromBits(c->DhParamBits));
+		}
 	}
 	Unlock(c->lock);
 
@@ -6289,6 +6301,7 @@ void SiWriteServerCfg(FOLDER *f, SERVER *s)
 	CfgAddBool(f, "BackupConfigOnlyWhenModified", s->BackupConfigOnlyWhenModified);
 
 	CfgAddIp(f, "ListenIP", &s->ListenIP);
+
 	if (s->Logger != NULL)
 	{
 		CfgAddInt(f, "ServerLogSwitchType", s->Logger->SwitchType);
@@ -6499,6 +6512,7 @@ void SiWriteServerCfg(FOLDER *f, SERVER *s)
 		CfgAddBool(f, "Tls_Disable1_0", c->SslAcceptSettings.Tls_Disable1_0);
 		CfgAddBool(f, "Tls_Disable1_1", c->SslAcceptSettings.Tls_Disable1_1);
 		CfgAddBool(f, "Tls_Disable1_2", c->SslAcceptSettings.Tls_Disable1_2);
+		CfgAddInt(f, "DhParamBits", c->DhParamBits);
 
 		// Disable session reconnect
 		CfgAddBool(f, "DisableSessionReconnect", GetGlobalServerFlag(GSF_DISABLE_SESSION_RECONNECT));
diff --git a/src/Mayaqua/Encrypt.c b/src/Mayaqua/Encrypt.c
index e403189f..389267b0 100644
--- a/src/Mayaqua/Encrypt.c
+++ b/src/Mayaqua/Encrypt.c
@@ -4895,12 +4895,36 @@ DH_CTX *DhNewGroup5()
 	return DhNew(DH_GROUP5_PRIME_1536, 2);
 }
 
+
 // Creating a DH SIMPLE 160bits
 DH_CTX *DhNewSimple160()
 {
 	return DhNew(DH_SIMPLE_160, 2);
 }
 
+DH_CTX *DhNewFromBits(UINT bits)
+{
+	switch (bits)
+	{
+	case 160:
+		return DhNewSimple160();
+	case 768:
+		return DhNewGroup1();
+	case 1024:
+		return DhNewGroup2();
+	case 1536:
+		return DhNewGroup5();
+	case 2048:
+		return DhNew2048();
+	case 3072:
+		return DhNew3072();
+	case 4096:
+		return DhNew4096();
+	default:
+		return DhNew2048();
+	}
+}
+
 // Convert the DH parameters to file
 BUF *DhToBuf(DH_CTX *dh)
 {
diff --git a/src/Mayaqua/Encrypt.h b/src/Mayaqua/Encrypt.h
index 8bd25818..117e9263 100644
--- a/src/Mayaqua/Encrypt.h
+++ b/src/Mayaqua/Encrypt.h
@@ -150,8 +150,8 @@ void RAND_Free_For_SoftEther();
 // HMAC block size
 #define	HMAC_BLOCK_SIZE					64
 // The block size for sha-384 and sha-512 as defined by rfc4868
-#define HMAC_BLOCK_SIZE_1024			128
-#define HMAC_BLOCK_SIZE_MAX				512
+#define HMAC_BLOCK_SIZE_1024					128
+#define HMAC_BLOCK_SIZE_MAX					512
 
 #define DH_GROUP1_PRIME_768 \
 	"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
@@ -540,6 +540,7 @@ DH_CTX *DhNewSimple160();
 DH_CTX *DhNew2048();
 DH_CTX *DhNew3072();
 DH_CTX *DhNew4096();
+DH_CTX *DhNewFromBits(UINT bits);
 DH_CTX *DhNew(char *prime, UINT g);
 void DhFree(DH_CTX *dh);
 BUF *DhToBuf(DH_CTX *dh);
diff --git a/src/Mayaqua/Network.c b/src/Mayaqua/Network.c
index a1d5c83c..f3d130fb 100644
--- a/src/Mayaqua/Network.c
+++ b/src/Mayaqua/Network.c
@@ -250,7 +250,7 @@ static UINT rand_port_numbers[256] = {0};
 static bool g_use_privateip_file = false;
 static bool g_source_ip_validation_force_disable = false;
 
-static DH_CTX *dh_2048 = NULL;
+static DH_CTX *dh_param = NULL;
 
 typedef struct PRIVATE_IP_SUBNET
 {
@@ -17810,9 +17810,9 @@ DH *TmpDhCallback(SSL *ssl, int is_export, int keylength)
 {
 	DH *ret = NULL;
 
-	if (dh_2048 != NULL)
+	if (dh_param != NULL)
 	{
-		ret = dh_2048->dh;
+		ret = dh_param->dh;
 	}
 
 	return ret;
@@ -17932,9 +17932,6 @@ void InitNetwork()
 
 	disable_cache = false;
 
-
-	dh_2048 = DhNew2048();
-
 	Zero(rand_port_numbers, sizeof(rand_port_numbers));
 
 	SetGetIpThreadMaxNum(DEFAULT_GETIP_THREAD_MAX_NUM);
@@ -18367,10 +18364,10 @@ void SetCurrentGlobalIP(IP *ip, bool ipv6)
 void FreeNetwork()
 {
 
-	if (dh_2048 != NULL)
+	if (dh_param != NULL)
 	{
-		DhFree(dh_2048);
-		dh_2048 = NULL;
+		DhFree(dh_param);
+		dh_param = NULL;
 	}
 
 	// Release of thread-related
@@ -20282,6 +20279,8 @@ LABEL_RESTART:
 
 		if (u->PollMyIpAndPort)
 		{
+			// Create a thread to get a NAT-T IP address if necessary
+			if (u->GetNatTIpThread == NULL)
 			{
 				// Create a thread to get a NAT-T IP address if necessary
 				if (u->GetNatTIpThread == NULL)
diff --git a/src/Mayaqua/Network.h b/src/Mayaqua/Network.h
index ffc96d07..870ef40f 100644
--- a/src/Mayaqua/Network.h
+++ b/src/Mayaqua/Network.h
@@ -1020,6 +1020,8 @@ int GetCurrentTimezone();
 bool GetSniNameFromSslPacket(UCHAR *packet_buf, UINT packet_size, char *sni, UINT sni_size);
 bool GetSniNameFromPreSslConnection(SOCK *s, char *sni, UINT sni_size);
 
+void SetDhParam(DH_CTX *dh);
+
 bool IsUseDnsProxy();
 bool IsUseAlternativeHostname();