diff --git a/src/ProxyServer/GCDHTTPProxyServer.swift b/src/ProxyServer/GCDHTTPProxyServer.swift
index c36b80ef3..b157989d8 100644
--- a/src/ProxyServer/GCDHTTPProxyServer.swift
+++ b/src/ProxyServer/GCDHTTPProxyServer.swift
@@ -17,7 +17,7 @@ public final class GCDHTTPProxyServer: GCDProxyServer {
 
      - parameter socket: The accepted socket.
      */
-    override func handleNewGCDSocket(_ socket: GCDTCPSocket) {
+    override open func handleNewGCDSocket(_ socket: GCDTCPSocket) {
         let proxySocket = HTTPProxySocket(socket: socket)
         didAcceptNewSocket(proxySocket)
     }
diff --git a/src/ProxyServer/GCDSOCKS5ProxyServer.swift b/src/ProxyServer/GCDSOCKS5ProxyServer.swift
index c46e467aa..979db361e 100644
--- a/src/ProxyServer/GCDSOCKS5ProxyServer.swift
+++ b/src/ProxyServer/GCDSOCKS5ProxyServer.swift
@@ -17,7 +17,7 @@ public final class GCDSOCKS5ProxyServer: GCDProxyServer {
 
      - parameter socket: The accepted socket.
      */
-    override func handleNewGCDSocket(_ socket: GCDTCPSocket) {
+    override open func handleNewGCDSocket(_ socket: GCDTCPSocket) {
         let proxySocket = SOCKS5ProxySocket(socket: socket)
         didAcceptNewSocket(proxySocket)
     }