diff --git a/client_http.hpp b/client_http.hpp
index 3e5a128..fcc47dd 100644
--- a/client_http.hpp
+++ b/client_http.hpp
@@ -501,7 +501,7 @@ namespace SimpleWeb {
             auto content_length = stoull(header_it->second);
             if(content_length > num_additional_bytes) {
               session->connection->set_timeout();
-              asio::async_read(*session->connection->socket, session->response->streambuf, asio::transfer_exactly(content_length - num_additional_bytes), [this, session](const error_code &ec, std::size_t /*bytes_transferred*/) {
+              asio::async_read(*session->connection->socket, session->response->streambuf, asio::transfer_exactly(content_length - num_additional_bytes), [session](const error_code &ec, std::size_t /*bytes_transferred*/) {
                 session->connection->cancel_timeout();
                 auto lock = session->connection->handler_runner->continue_lock();
                 if(!lock)
@@ -526,7 +526,7 @@ namespace SimpleWeb {
           }
           else if(session->response->http_version < "1.1" || ((header_it = session->response->header.find("Session")) != session->response->header.end() && header_it->second == "close")) {
             session->connection->set_timeout();
-            asio::async_read(*session->connection->socket, session->response->streambuf, [this, session](const error_code &ec, std::size_t /*bytes_transferred*/) {
+            asio::async_read(*session->connection->socket, session->response->streambuf, [session](const error_code &ec, std::size_t /*bytes_transferred*/) {
               session->connection->cancel_timeout();
               auto lock = session->connection->handler_runner->continue_lock();
               if(!lock)
diff --git a/server_http.hpp b/server_http.hpp
index c5389e9..e282bcb 100644
--- a/server_http.hpp
+++ b/server_http.hpp
@@ -286,7 +286,7 @@ namespace SimpleWeb {
       Config(unsigned short port) noexcept : port(port) {}
 
     public:
-      /// Port number to use. Defaults to 80 for HTTP and 443 for HTTPS.
+      /// Port number to use. Defaults to 80 for HTTP and 443 for HTTPS. Set to 0 get an assigned port.
       unsigned short port;
       /// If io_service is not set, number of threads that the server will use when start() is called.
       /// Defaults to 1 thread.
@@ -332,35 +332,43 @@ namespace SimpleWeb {
     /// If you have your own asio::io_service, store its pointer here before running start().
     std::shared_ptr<asio::io_service> io_service;
 
-    virtual unsigned short bindAndPrepare() {
-      if(!io_service) {
-        io_service = std::make_shared<asio::io_service>();
-        internal_io_service = true;
-      }
-
-      if(io_service->stopped())
-        io_service->reset();
-
+    /// If you know the server port in advance, use start() instead.
+    /// Returns assigned port. If io_service is not set, an internal io_service is created instead.
+    /// Call before accept_and_run().
+    unsigned short bind() {
       asio::ip::tcp::endpoint endpoint;
       if(config.address.size() > 0)
         endpoint = asio::ip::tcp::endpoint(asio::ip::address::from_string(config.address), config.port);
       else
         endpoint = asio::ip::tcp::endpoint(asio::ip::tcp::v4(), config.port);
 
+      if(!io_service) {
+        io_service = std::make_shared<asio::io_service>();
+        internal_io_service = true;
+      }
+
       if(!acceptor)
         acceptor = std::unique_ptr<asio::ip::tcp::acceptor>(new asio::ip::tcp::acceptor(*io_service));
       acceptor->open(endpoint.protocol());
       acceptor->set_option(asio::socket_base::reuse_address(config.reuse_address));
       acceptor->bind(endpoint);
-      acceptor->listen();
 
-      accept();
+      after_bind();
 
       return acceptor->local_endpoint().port();
     }
 
-    virtual void runServer() {
+    /// If you know the server port in advance, use start() instead.
+    /// Accept requests, and if io_service was not set before calling bind(), run the internal io_service instead.
+    /// Call after bind().
+    void accept_and_run() {
+      acceptor->listen();
+      accept();
+
       if(internal_io_service) {
+        if(io_service->stopped())
+          io_service->reset();
+
         // If thread_pool_size>1, start m_io_service.run() in (thread_pool_size-1) threads for thread-pooling
         threads.clear();
         for(std::size_t c = 1; c < config.thread_pool_size; c++) {
@@ -379,9 +387,10 @@ namespace SimpleWeb {
       }
     }
 
-    virtual void start() {
-      bindAndPrepare();
-      runServer();
+    /// Start the server by calling bind() and accept_and_run()
+    void start() {
+      bind();
+      accept_and_run();
     }
 
     /// Stop accepting new requests, and close current connections.
@@ -420,6 +429,7 @@ namespace SimpleWeb {
 
     ServerBase(unsigned short port) noexcept : config(port), connections(new std::unordered_set<Connection *>()), connections_mutex(new std::mutex()), handler_runner(new ScopeRunner()) {}
 
+    virtual void after_bind() {}
     virtual void accept() = 0;
 
     template <typename... Args>
diff --git a/server_https.hpp b/server_https.hpp
index 4840b82..0746f4f 100644
--- a/server_https.hpp
+++ b/server_https.hpp
@@ -17,7 +17,6 @@ namespace SimpleWeb {
 
   template <>
   class Server<HTTPS> : public ServerBase<HTTPS> {
-    std::string session_id_context;
     bool set_session_id_context = false;
 
   public:
@@ -33,20 +32,19 @@ namespace SimpleWeb {
       }
     }
 
-    void start() override {
+  protected:
+    asio::ssl::context context;
+
+    void after_bind() override {
       if(set_session_id_context) {
         // Creating session_id_context from address:port but reversed due to small SSL_MAX_SSL_SESSION_ID_LENGTH
-        session_id_context = std::to_string(config.port) + ':';
+        auto session_id_context = std::to_string(acceptor->local_endpoint().port()) + ':';
         session_id_context.append(config.address.rbegin(), config.address.rend());
         SSL_CTX_set_session_id_context(context.native_handle(), reinterpret_cast<const unsigned char *>(session_id_context.data()),
                                        std::min<std::size_t>(session_id_context.size(), SSL_MAX_SSL_SESSION_ID_LENGTH));
       }
-      ServerBase::start();
     }
 
-  protected:
-    asio::ssl::context context;
-
     void accept() override {
       auto connection = create_connection(*io_service, context);