diff --git a/Sources/OpenVPNAdapter/OpenVPNAdapter.mm b/Sources/OpenVPNAdapter/OpenVPNAdapter.mm
index a5c4e01..8d4795c 100644
--- a/Sources/OpenVPNAdapter/OpenVPNAdapter.mm
+++ b/Sources/OpenVPNAdapter/OpenVPNAdapter.mm
@@ -172,6 +172,7 @@
 
 - (BOOL)addIPV4Address:(NSString *)address subnetMask:(NSString *)subnetMask gateway:(NSString *)gateway {
     self.networkSettingsBuilder.ipv4DefaultGateway = gateway;
+    
     [self.networkSettingsBuilder.ipv4LocalAddresses addObject:address];
     [self.networkSettingsBuilder.ipv4SubnetMasks addObject:subnetMask];
     
@@ -180,6 +181,7 @@
 
 - (BOOL)addIPV6Address:(NSString *)address prefixLength:(NSNumber *)prefixLength gateway:(NSString *)gateway {
     self.networkSettingsBuilder.ipv6DefaultGateway = gateway;
+    
     [self.networkSettingsBuilder.ipv6LocalAddresses addObject:address];
     [self.networkSettingsBuilder.ipv6NetworkPrefixLengths addObject:prefixLength];
     
@@ -188,34 +190,78 @@
 
 - (BOOL)addIPV4Route:(NEIPv4Route *)route {
     route.gatewayAddress = self.networkSettingsBuilder.ipv4DefaultGateway;
-    [self.networkSettingsBuilder.ipv4IncludedRoutes addObject:route];
     
-    return YES;
+    NSUInteger index = [self.networkSettingsBuilder.ipv4IncludedRoutes indexOfObjectPassingTest:^BOOL(NEIPv4Route *obj, NSUInteger idx, BOOL *stop) {
+        return [obj.destinationAddress isEqualToString:route.destinationAddress] &&
+            [obj.destinationSubnetMask isEqualToString:route.destinationSubnetMask];
+    }];
+    
+    if (index == NSNotFound) {
+        [self.networkSettingsBuilder.ipv4IncludedRoutes addObject:route];
+        return YES;
+    } else {
+        return NO;
+    }
 }
 
 - (BOOL)addIPV6Route:(NEIPv6Route *)route {
     route.gatewayAddress = self.networkSettingsBuilder.ipv6DefaultGateway;
-    [self.networkSettingsBuilder.ipv6IncludedRoutes addObject:route];
     
-    return YES;
+    NSUInteger index = [self.networkSettingsBuilder.ipv6IncludedRoutes indexOfObjectPassingTest:^BOOL(NEIPv6Route *obj, NSUInteger idx, BOOL *stop) {
+        return [obj.destinationAddress isEqualToString:route.destinationAddress] &&
+            obj.destinationNetworkPrefixLength == route.destinationNetworkPrefixLength;
+    }];
+    
+    if (index == NSNotFound) {
+        [self.networkSettingsBuilder.ipv6IncludedRoutes addObject:route];
+        return YES;
+    } else {
+        return NO;
+    }
 }
 
 - (BOOL)excludeIPV4Route:(NEIPv4Route *)route {
-    [self.networkSettingsBuilder.ipv4ExcludedRoutes addObject:route];
-    return YES;
+    NSUInteger index = [self.networkSettingsBuilder.ipv4ExcludedRoutes indexOfObjectPassingTest:^BOOL(NEIPv4Route *obj, NSUInteger idx, BOOL *stop) {
+        return [obj.destinationAddress isEqualToString:route.destinationAddress] &&
+        [obj.destinationSubnetMask isEqualToString:route.destinationSubnetMask];
+    }];
+    
+    if (index == NSNotFound) {
+        [self.networkSettingsBuilder.ipv4ExcludedRoutes addObject:route];
+        return YES;
+    } else {
+        return NO;
+    }
 }
 
 - (BOOL)excludeIPV6Route:(NEIPv6Route *)route {
-    [self.networkSettingsBuilder.ipv6ExcludedRoutes addObject:route];
-    return YES;
+    NSUInteger index = [self.networkSettingsBuilder.ipv6ExcludedRoutes indexOfObjectPassingTest:^BOOL(NEIPv6Route *obj, NSUInteger idx, BOOL *stop) {
+        return [obj.destinationAddress isEqualToString:route.destinationAddress] &&
+        obj.destinationNetworkPrefixLength == route.destinationNetworkPrefixLength;
+    }];
+    
+    if (index == NSNotFound) {
+        [self.networkSettingsBuilder.ipv6ExcludedRoutes addObject:route];
+        return YES;
+    } else {
+        return NO;
+    }
 }
 
 - (BOOL)addDNS:(NSString *)dns {
+    if ([self.networkSettingsBuilder.dnsServers containsObject:dns]) {
+        return NO;
+    }
+    
     [self.networkSettingsBuilder.dnsServers addObject:dns];
     return YES;
 }
 
 - (BOOL)addSearchDomain:(NSString *)domain {
+    if ([self.networkSettingsBuilder.searchDomains containsObject:domain]) {
+        return NO;
+    }
+    
     [self.networkSettingsBuilder.searchDomains addObject:domain];
     return YES;
 }
@@ -231,6 +277,10 @@
 }
 
 - (BOOL)addProxyBypassHost:(NSString *)bypassHost {
+    if ([self.networkSettingsBuilder.proxyExceptionList containsObject:bypassHost]) {
+        return NO;
+    }
+    
     [self.networkSettingsBuilder.proxyExceptionList addObject:bypassHost];
     return YES;
 }
diff --git a/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.h b/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.h
index d56b5fb..63903d2 100644
--- a/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.h
+++ b/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.h
@@ -33,10 +33,10 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, readonly) NSMutableArray<NEIPv6Route *> *ipv6IncludedRoutes;
 @property (nonatomic, readonly) NSMutableArray<NEIPv6Route *> *ipv6ExcludedRoutes;
 
-@property (nonatomic, readonly) NSMutableSet<NSString *> *dnsServers;
-@property (nonatomic, readonly) NSMutableSet<NSString *> *searchDomains;
+@property (nonatomic, readonly) NSMutableArray<NSString *> *dnsServers;
+@property (nonatomic, readonly) NSMutableArray<NSString *> *searchDomains;
 
-@property (nonatomic, readonly) NSMutableSet<NSString *> *proxyExceptionList;
+@property (nonatomic, readonly) NSMutableArray<NSString *> *proxyExceptionList;
 
 @property (nonatomic) BOOL autoProxyConfigurationEnabled;
 @property (nonatomic, copy, nullable) NSURL *proxyAutoConfigurationURL;
diff --git a/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.m b/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.m
index c70843a..f95433c 100644
--- a/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.m
+++ b/Sources/OpenVPNAdapter/OpenVPNNetworkSettingsBuilder.m
@@ -14,8 +14,6 @@
 
 @interface OpenVPNNetworkSettingsBuilder ()
 
-// TODO: Use NSHashTable for routes to avoid duplicates
-
 @property (nonatomic) NSMutableArray<NSString *> *ipv4LocalAddresses;
 @property (nonatomic) NSMutableArray<NSString *> *ipv4SubnetMasks;
 @property (nonatomic) NSMutableArray<NEIPv4Route *> *ipv4IncludedRoutes;
@@ -26,10 +24,10 @@
 @property (nonatomic) NSMutableArray<NEIPv6Route *> *ipv6IncludedRoutes;
 @property (nonatomic) NSMutableArray<NEIPv6Route *> *ipv6ExcludedRoutes;
 
-@property (nonatomic) NSMutableSet<NSString *> *dnsServers;
-@property (nonatomic) NSMutableSet<NSString *> *searchDomains;
+@property (nonatomic) NSMutableArray<NSString *> *dnsServers;
+@property (nonatomic) NSMutableArray<NSString *> *searchDomains;
 
-@property (nonatomic) NSMutableSet<NSString *> *proxyExceptionList;
+@property (nonatomic) NSMutableArray<NSString *> *proxyExceptionList;
 
 @end
 
@@ -67,8 +65,8 @@
     }
     
     if (self.dnsServers.ovpn_isNotEmpty) {
-        NEDNSSettings *dnsSettings = [[NEDNSSettings alloc] initWithServers:self.dnsServers.allObjects];
-        dnsSettings.searchDomains = self.searchDomains.allObjects;
+        NEDNSSettings *dnsSettings = [[NEDNSSettings alloc] initWithServers:self.dnsServers];
+        dnsSettings.searchDomains = self.searchDomains;
         networkSettings.DNSSettings = dnsSettings;
     }
     
@@ -77,7 +75,7 @@
         
         proxySettings.autoProxyConfigurationEnabled = self.autoProxyConfigurationEnabled;
         proxySettings.proxyAutoConfigurationURL = self.proxyAutoConfigurationURL;
-        proxySettings.exceptionList = self.proxyExceptionList.allObjects;
+        proxySettings.exceptionList = self.proxyExceptionList;
         proxySettings.HTTPServer = self.httpProxyServer;
         proxySettings.HTTPEnabled = self.httpProxyServerEnabled;
         proxySettings.HTTPSServer = self.httpsProxyServer;
@@ -133,18 +131,18 @@
     return _ipv6ExcludedRoutes;
 }
 
-- (NSMutableSet<NSString *> *)dnsServers {
-    if (!_dnsServers) { _dnsServers = [[NSMutableSet alloc] init]; }
+- (NSMutableArray<NSString *> *)dnsServers {
+    if (!_dnsServers) { _dnsServers = [[NSMutableArray alloc] init]; }
     return _dnsServers;
 }
 
-- (NSMutableSet<NSString *> *)searchDomains {
-    if (!_searchDomains) { _searchDomains = [[NSMutableSet alloc] init]; }
+- (NSMutableArray<NSString *> *)searchDomains {
+    if (!_searchDomains) { _searchDomains = [[NSMutableArray alloc] init]; }
     return _searchDomains;
 }
 
-- (NSMutableSet<NSString *> *)proxyExceptionList {
-    if (!_proxyExceptionList) { _proxyExceptionList = [[NSMutableSet alloc] init]; }
+- (NSMutableArray<NSString *> *)proxyExceptionList {
+    if (!_proxyExceptionList) { _proxyExceptionList = [[NSMutableArray alloc] init]; }
     return _proxyExceptionList;
 }