diff --git a/src/Cedar/Command.c b/src/Cedar/Command.c
index 372baa54..c11455cc 100644
--- a/src/Cedar/Command.c
+++ b/src/Cedar/Command.c
@@ -67,13 +67,26 @@ void CheckNetworkListenThread(THREAD *thread, void *param)
 {
 	CHECK_NETWORK_1 *c = (CHECK_NETWORK_1 *)param;
 	SOCK *s;
-	UINT i;
+	UINT i, rsa_bits = 1024;
 	K *pub, *pri;
 	X *x;
 	LIST *o = NewList(NULL);
 	NAME *name = NewName(L"Test", L"Test", L"Test", L"JP", L"Ibaraki", L"Tsukuba");
 
-	RsaGen(&pri, &pub, 1024);
+	// Set RSA bits considering OpenSSL security Level
+	// Security level 4 needs 7680 bits
+	switch (GetOSSecurityLevel())
+	{
+	case 2:
+		rsa_bits = 2048;
+		break;
+	case 3:
+		rsa_bits = 4096;
+		break;
+	default:
+		break;
+	}
+	RsaGen(&pri, &pub, rsa_bits);
 	x = NewRootX(pub, pri, name, 1000, NULL);
 
 	FreeName(name);
diff --git a/src/Cedar/Server.c b/src/Cedar/Server.c
index fcd0c2bd..f606fd29 100644
--- a/src/Cedar/Server.c
+++ b/src/Cedar/Server.c
@@ -5931,6 +5931,8 @@ void SiLoadServerCfg(SERVER *s, FOLDER *f)
 		c->SslAcceptSettings.Tls_Disable1_1 = CfgGetBool(f, "Tls_Disable1_1");
 		c->SslAcceptSettings.Tls_Disable1_2 = CfgGetBool(f, "Tls_Disable1_2");
 		c->SslAcceptSettings.Tls_Disable1_3 = CfgGetBool(f, "Tls_Disable1_3");
+		c->SslAcceptSettings.Override_Security_Level = CfgGetBool(f, "Override_Security_Level");
+		c->SslAcceptSettings.Override_Security_Level_Value = CfgGetInt(f, "Override_Security_Level_Value");
 
 		s->StrictSyslogDatetimeFormat = CfgGetBool(f, "StrictSyslogDatetimeFormat");
 
@@ -6256,6 +6258,8 @@ void SiWriteServerCfg(FOLDER *f, SERVER *s)
 		CfgAddBool(f, "Tls_Disable1_1", c->SslAcceptSettings.Tls_Disable1_1);
 		CfgAddBool(f, "Tls_Disable1_2", c->SslAcceptSettings.Tls_Disable1_2);
 		CfgAddBool(f, "Tls_Disable1_3", c->SslAcceptSettings.Tls_Disable1_3);
+		CfgAddBool(f, "Override_Security_Level", c->SslAcceptSettings.Override_Security_Level);
+		CfgAddInt(f, "Override_Security_Level_Value", c->SslAcceptSettings.Override_Security_Level_Value);
 		CfgAddInt(f, "DhParamBits", c->DhParamBits);
 
 		// Disable session reconnect
diff --git a/src/Mayaqua/Network.c b/src/Mayaqua/Network.c
index bbe4b1ad..ed1e1c9a 100644
--- a/src/Mayaqua/Network.c
+++ b/src/Mayaqua/Network.c
@@ -5737,12 +5737,6 @@ SSL_PIPE *NewSslPipeEx(bool server_mode, X *x, K *k, DH_CTX *dh, bool verify_pee
 	{
 		if (server_mode)
 		{
-			SSL_CTX_set_ssl_version(ssl_ctx, SSLv23_server_method());
-
-#ifdef	SSL_OP_NO_SSLv3
-			SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv3);
-#endif	// SSL_OP_NO_SSLv3
-
 #ifdef SSL_OP_NO_TLSv1_3
 			SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1_3); // For some reason pppd under linux doesn't like it
 #endif
@@ -5753,10 +5747,16 @@ SSL_PIPE *NewSslPipeEx(bool server_mode, X *x, K *k, DH_CTX *dh, bool verify_pee
 			{
 				SSL_CTX_set_tmp_dh(ssl_ctx, dh->dh);
 			}
-		}
-		else
-		{
-			SSL_CTX_set_ssl_version(ssl_ctx, SSLv23_client_method());
+
+#if 0
+			// Cannot get config
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
+			if (sock->SslAcceptSettings.Override_Security_Level)
+			{
+				SSL_CTX_set_security_level(ssl_ctx, sock->SslAcceptSettings.Override_Security_Level_Value);
+			}
+#endif
+#endif
 		}
 
 		if (verify_peer)
@@ -12120,12 +12120,6 @@ bool StartSSLEx(SOCK *sock, X *x, K *priv, UINT ssl_timeout, char *sni_hostname)
 	{
 		if (sock->ServerMode)
 		{
-			SSL_CTX_set_ssl_version(ssl_ctx, SSLv23_server_method());
-
-#ifdef	SSL_OP_NO_SSLv3
-			SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv3);
-#endif	// SSL_OP_NO_SSLv3
-
 #ifdef	SSL_OP_NO_TLSv1
 			if (sock->SslAcceptSettings.Tls_Disable1_0)
 			{
@@ -12154,18 +12148,17 @@ bool StartSSLEx(SOCK *sock, X *x, K *priv, UINT ssl_timeout, char *sni_hostname)
 			}
 #endif	// SSL_OP_NO_TLSv1_3
 
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
+			if (sock->SslAcceptSettings.Override_Security_Level)
+			{
+				SSL_CTX_set_security_level(ssl_ctx, sock->SslAcceptSettings.Override_Security_Level_Value);
+			}
+#endif
+
 			Unlock(openssl_lock);
 			AddChainSslCertOnDirectory(ssl_ctx);
 			Lock(openssl_lock);
 		}
-		else
-		{
-			SSL_CTX_set_ssl_version(ssl_ctx, SSLv23_client_method());
-
-#ifdef	SSL_OP_NO_SSLv3
-			SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv3);
-#endif	// SSL_OP_NO_SSLv3
-		}
 
 		sock->ssl = SSL_new(ssl_ctx);
 		SSL_set_fd(sock->ssl, (int)sock->socket);
@@ -16819,6 +16812,20 @@ struct ssl_ctx_st *NewSSLCtx(bool server_mode)
 {
 	struct ssl_ctx_st *ctx = SSL_CTX_new(SSLv23_method());
 
+	// It resets some parameters.
+	if (server_mode)
+	{
+		SSL_CTX_set_ssl_version(ctx, SSLv23_server_method());
+	}
+	else
+	{
+		SSL_CTX_set_ssl_version(ctx, SSLv23_client_method());
+	}
+
+#ifdef	SSL_OP_NO_SSLv3
+	SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv3);
+#endif	// SSL_OP_NO_SSLv3
+
 #ifdef	SSL_OP_NO_TICKET
 	SSL_CTX_set_options(ctx, SSL_OP_NO_TICKET);
 #endif	// SSL_OP_NO_TICKET
@@ -16851,6 +16858,28 @@ void FreeSSLCtx(struct ssl_ctx_st *ctx)
 	SSL_CTX_free(ctx);
 }
 
+// Get OS (maximum) Security Level
+UINT GetOSSecurityLevel()
+{
+	UINT security_level_new = 0, security_level_set_ssl_version = 0;
+	struct ssl_ctx_st *ctx = SSL_CTX_new(SSLv23_method());
+
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
+	security_level_new = SSL_CTX_get_security_level(ctx);
+#endif
+
+	security_level_set_ssl_version = SSL_CTX_set_ssl_version(ctx, SSLv23_server_method());
+
+	FreeSSLCtx(ctx);
+
+	if(security_level_new >= security_level_set_ssl_version)
+	{
+		return security_level_new;
+	}
+
+	return security_level_set_ssl_version;
+}
+
 // The number of get ip threads
 void SetGetIpThreadMaxNum(UINT num)
 {
@@ -16966,12 +16995,6 @@ TOKEN_LIST *GetCipherList()
 		return ciphers;
 	}
 
-	SSL_CTX_set_ssl_version(ctx, SSLv23_server_method());
-
-#ifdef	SSL_OP_NO_SSLv3
-	SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv3);
-#endif
-
 	ssl = SSL_new(ctx);
 	if (ssl == NULL)
 	{
diff --git a/src/Mayaqua/Network.h b/src/Mayaqua/Network.h
index 8f1a44f2..bd4b535d 100644
--- a/src/Mayaqua/Network.h
+++ b/src/Mayaqua/Network.h
@@ -148,6 +148,8 @@ struct SSL_ACCEPT_SETTINGS
 	bool Tls_Disable1_1;
 	bool Tls_Disable1_2;
 	bool Tls_Disable1_3;
+	bool Override_Security_Level;
+	UINT Override_Security_Level_Value;
 };
 
 // Socket
@@ -1448,6 +1450,7 @@ void RefreshLocalMacAddressList();
 
 struct ssl_ctx_st *NewSSLCtx(bool server_mode);
 void FreeSSLCtx(struct ssl_ctx_st *ctx);
+UINT GetOSSecurityLevel();
 
 void SetCurrentDDnsFqdn(char *name);
 void GetCurrentDDnsFqdn(char *name, UINT size);