diff --git a/src/nghttp.cc b/src/nghttp.cc
index fa763d40..3c2284ea 100644
--- a/src/nghttp.cc
+++ b/src/nghttp.cc
@@ -105,6 +105,7 @@ Config::Config()
       window_bits(-1),
       connection_window_bits(-1),
       verbose(0),
+      port_override(0),
       null_out(false),
       remote_name(false),
       get_assets(false),
@@ -178,7 +179,57 @@ void Request::init_inflater() {
   assert(rv == 0);
 }
 
-void Request::init_html_parser() { html_parser = new HtmlParser(uri); }
+StringRef Request::get_real_scheme() const {
+  return config.scheme_override.empty()
+             ? util::get_uri_field(uri.c_str(), u, UF_SCHEMA)
+             : StringRef{config.scheme_override};
+}
+
+StringRef Request::get_real_host() const {
+  return config.host_override.empty()
+             ? util::get_uri_field(uri.c_str(), u, UF_HOST)
+             : StringRef{config.host_override};
+}
+
+uint16_t Request::get_real_port() const {
+  auto scheme = get_real_scheme();
+  return config.host_override.empty()
+             ? util::has_uri_field(u, UF_PORT) ? u.port
+                                               : scheme == "https" ? 443 : 80
+             : config.port_override == 0 ? scheme == "https" ? 443 : 80
+                                         : config.port_override;
+}
+
+void Request::init_html_parser() {
+  // We crawl HTML using overridden scheme, host, and port.
+  auto scheme = get_real_scheme();
+  auto host = get_real_host();
+  auto port = get_real_port();
+  auto ipv6_lit =
+      std::find(std::begin(host), std::end(host), ':') != std::end(host);
+
+  auto base_uri = scheme.str();
+  base_uri += "://";
+  if (ipv6_lit) {
+    base_uri += '[';
+  }
+  base_uri += host;
+  if (ipv6_lit) {
+    base_uri += ']';
+  }
+  if (!((scheme == "https" && port == 443) ||
+        (scheme == "http" && port == 80))) {
+    base_uri += ':';
+    base_uri += util::utos(port);
+  }
+  base_uri += util::get_uri_field(uri.c_str(), u, UF_PATH);
+  if (util::has_uri_field(u, UF_QUERY)) {
+    base_uri += '?';
+    base_uri += util::get_uri_field(uri.c_str(), u, UF_QUERY);
+  }
+
+  html_parser = new HtmlParser(base_uri);
+}
 
 int Request::update_html_parser(const uint8_t *data, size_t len, int fin) {
   if (!html_parser) {
@@ -625,20 +676,11 @@ int HttpClient::initiate_connection() {
 
       // If the user overrode the :authority or host header, use that
       // value for the SNI extension
-      const char *host_string = nullptr;
-      auto i =
-          std::find_if(std::begin(config.headers), std::end(config.headers),
-                       [](const Header &nv) {
-                         return ":authority" == nv.name || "host" == nv.name;
-                       });
-      if (i != std::end(config.headers)) {
-        host_string = (*i).value.c_str();
-      } else {
-        host_string = host.c_str();
-      }
+      const auto &host_string =
+          config.host_override.empty() ? host : config.host_override;
 
-      if (!util::numeric_host(host_string)) {
-        SSL_set_tlsext_host_name(ssl, host_string);
+      if (!util::numeric_host(host_string.c_str())) {
+        SSL_set_tlsext_host_name(ssl, host_string.c_str());
       }
     }
 
@@ -1591,35 +1633,36 @@ void update_html_parser(HttpClient *client, Request *req, const uint8_t *data,
   }
   req->update_html_parser(data, len, fin);
 
+  auto scheme = req->get_real_scheme();
+  auto host = req->get_real_host();
+  auto port = req->get_real_port();
+
   for (auto &p : req->html_parser->get_links()) {
     auto uri = strip_fragment(p.first.c_str());
     auto res_type = p.second;
 
     http_parser_url u{};
-    if (http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) == 0) {
+    if (http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) != 0) {
+      continue;
+    }
 
-      const char *host_string = nullptr;
-      auto found =
-          std::find_if(std::begin(config.headers), std::end(config.headers),
-                       [](const Header &nv) {
-                         return ":authority" == nv.name || "host" == nv.name;
-                       });
-      if (found != std::end(config.headers)) {
-        host_string = (*found).value.c_str();
-      }
+    if (!util::fieldeq(uri.c_str(), u, UF_SCHEMA, scheme) ||
+        !util::fieldeq(uri.c_str(), u, UF_HOST, host)) {
+      continue;
+    }
 
-      if (util::fieldeq(uri.c_str(), u, req->uri.c_str(), req->u, UF_SCHEMA) &&
-          (util::fieldeq(uri.c_str(), u, req->uri.c_str(), req->u, UF_HOST) ||
-           (host_string != nullptr &&
-            util::fieldeq(uri.c_str(), u, UF_HOST, host_string))) &&
-          util::porteq(uri.c_str(), u, req->uri.c_str(), req->u)) {
-        // No POST data for assets
-        auto pri_spec = resolve_dep(res_type);
+    auto link_port =
+        util::has_uri_field(u, UF_PORT) ? u.port : scheme == "https" ? 443 : 80;
 
-        if (client->add_request(uri, nullptr, 0, pri_spec, req->level + 1)) {
-          submit_request(client, config.headers, client->reqvec.back().get());
-        }
-      }
+    if (port != link_port) {
+      continue;
+    }
+
+    // No POST data for assets
+    auto pri_spec = resolve_dep(res_type);
+
+    if (client->add_request(uri, nullptr, 0, pri_spec, req->level + 1)) {
+      submit_request(client, config.headers, client->reqvec.back().get());
     }
   }
   req->html_parser->clear_links();
@@ -2945,6 +2988,41 @@ int main(int argc, char **argv) {
   }
   config.weight.insert(std::end(config.weight), argc - optind, weight_to_fill);
 
+  // Find scheme overridden by extra header fields.
+  auto scheme_it =
+      std::find_if(std::begin(config.headers), std::end(config.headers),
+                   [](const Header &nv) { return nv.name == ":scheme"; });
+  if (scheme_it != std::end(config.headers)) {
+    config.scheme_override = (*scheme_it).value;
+  }
+
+  // Find host and port overridden by extra header fields.
+  auto authority_it =
+      std::find_if(std::begin(config.headers), std::end(config.headers),
+                   [](const Header &nv) { return nv.name == ":authority"; });
+  if (authority_it == std::end(config.headers)) {
+    authority_it =
+        std::find_if(std::begin(config.headers), std::end(config.headers),
+                     [](const Header &nv) { return nv.name == "host"; });
+  }
+
+  if (authority_it != std::end(config.headers)) {
+    // authority_it may looks like "host:port".
+    auto uri = "https://" + (*authority_it).value;
+    http_parser_url u{};
+    if (http_parser_parse_url(uri.c_str(), uri.size(), 0, &u) != 0) {
+      std::cerr << "[ERROR] Could not parse authority in "
+                << (*authority_it).name << ": " << (*authority_it).value
+                << std::endl;
+      exit(EXIT_FAILURE);
+    }
+
+    config.host_override = util::get_uri_field(uri.c_str(), u, UF_HOST).str();
+    if (util::has_uri_field(u, UF_PORT)) {
+      config.port_override = u.port;
+    }
+  }
+
   set_color_output(color || isatty(fileno(stdout)));
 
   nghttp2_option_set_peer_max_concurrent_streams(
diff --git a/src/nghttp.h b/src/nghttp.h
index eb36a4ce..ccc2230c 100644
--- a/src/nghttp.h
+++ b/src/nghttp.h
@@ -69,6 +69,8 @@ struct Config {
   std::string keyfile;
   std::string datafile;
   std::string harfile;
+  std::string scheme_override;
+  std::string host_override;
   nghttp2_option *http2_option;
   int64_t header_table_size;
   int64_t min_header_table_size;
@@ -82,6 +84,7 @@ struct Config {
   int window_bits;
   int connection_window_bits;
   int verbose;
+  uint16_t port_override;
   bool null_out;
   bool remote_name;
   bool get_assets;
@@ -151,6 +154,15 @@ struct Request {
   void record_response_start_time();
   void record_response_end_time();
 
+  // Returns scheme taking into account overridden scheme.
+  StringRef get_real_scheme() const;
+  // Returns request host, without port, taking into account
+  // overridden host.
+  StringRef get_real_host() const;
+  // Returns request port, taking into account overridden host, port,
+  // and scheme.
+  uint16_t get_real_port() const;
+
   Headers res_nva;
   Headers req_nva;
   std::string method;
diff --git a/src/util.cc b/src/util.cc
index 587fee51..8dec1d97 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -555,20 +555,16 @@ bool fieldeq(const char *uri1, const http_parser_url &u1, const char *uri2,
 
 bool fieldeq(const char *uri, const http_parser_url &u,
              http_parser_url_fields field, const char *t) {
+  return fieldeq(uri, u, field, StringRef{t});
+}
+
+bool fieldeq(const char *uri, const http_parser_url &u,
+             http_parser_url_fields field, const StringRef &t) {
   if (!has_uri_field(u, field)) {
-    if (!t[0]) {
-      return true;
-    } else {
-      return false;
-    }
-  } else if (!t[0]) {
-    return false;
+    return t.empty();
   }
-  int i, len = u.field_data[field].len;
-  const char *p = uri + u.field_data[field].off;
-  for (i = 0; i < len && t[i] && p[i] == t[i]; ++i)
-    ;
-  return i == len && !t[i];
+  auto &f = u.field_data[field];
+  return StringRef{uri + f.off, f.len} == t;
 }
 
 StringRef get_uri_field(const char *uri, const http_parser_url &u,
diff --git a/src/util.h b/src/util.h
index 3bf5ff92..39280b4d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -461,6 +461,9 @@ bool fieldeq(const char *uri1, const http_parser_url &u1, const char *uri2,
 bool fieldeq(const char *uri, const http_parser_url &u,
              http_parser_url_fields field, const char *t);
 
+bool fieldeq(const char *uri, const http_parser_url &u,
+             http_parser_url_fields field, const StringRef &t);
+
 StringRef get_uri_field(const char *uri, const http_parser_url &u,
                         http_parser_url_fields field);