diff --git a/tests/httpserver.pl b/tests/httpserver.pl
index 05ec80a..58ab5d4 100755
--- a/tests/httpserver.pl
+++ b/tests/httpserver.pl
@@ -44,8 +44,9 @@
 my $ipvnum = 4;      # default IP version of http server
 my $idnum = 1;       # default http server instance number
 my $proto = 'http';  # protocol the http server speaks
-my $pidfile;         # http server pid file
-my $logfile;         # http server log file
+my $pidfile;         # pid file
+my $portfile;        # port number file
+my $logfile;         # log file
 my $connect;         # IP to connect to on CONNECT
 my $srcdir;
 my $gopher = 0;
@@ -61,6 +62,12 @@
             shift @ARGV;
         }
     }
+    elsif($ARGV[0] eq '--portfile') {
+        if($ARGV[1]) {
+            $portfile = $ARGV[1];
+            shift @ARGV;
+        }
+    }
     elsif($ARGV[0] eq '--logfile') {
         if($ARGV[1]) {
             $logfile = $ARGV[1];
@@ -122,11 +129,16 @@
 if(!$pidfile) {
     $pidfile = "$path/". server_pidfilename($proto, $ipvnum, $idnum);
 }
+if(!$portfile) {
+    $portfile = "$path/". server_portfilename($proto, $ipvnum, $idnum);
+}
 if(!$logfile) {
     $logfile = server_logfilename($logdir, $proto, $ipvnum, $idnum);
 }
 
-$flags .= "--pidfile \"$pidfile\" --logfile \"$logfile\" ";
+$flags .= "--pidfile \"$pidfile\" ".
+    "--logfile \"$logfile\" ".
+    "--portfile \"$portfile\" ";
 $flags .= "--gopher " if($gopher);
 $flags .= "--connect $connect " if($connect);
 if($ipvnum eq 'unix') {
diff --git a/tests/runtests.pl b/tests/runtests.pl
index c44b03f..549db52 100755
--- a/tests/runtests.pl
+++ b/tests/runtests.pl
@@ -1498,6 +1498,7 @@
     $server = servername_id($proto, $ipvnum, $idnum);
 
     $pidfile = $serverpidfile{$server};
+    my $portfile = $serverportfile{$server};
 
     # don't retry if the server doesn't work
     if ($doesntrun{$pidfile}) {
@@ -1518,11 +1519,12 @@
     $flags .= "--connect $HOSTIP " if($alt eq "proxy");
     $flags .= $verbose_flag if($debugprotocol);
     $flags .= "--pidfile \"$pidfile\" --logfile \"$logfile\" ";
+    $flags .= "--portfile $portfile ";
     $flags .= "--id $idnum " if($idnum > 1);
     if($ipvnum eq "unix") {
         $flags .= "--unix-socket '$port_or_path' ";
     } else {
-        $flags .= "--ipv$ipvnum --port $port_or_path ";
+        $flags .= "--ipv$ipvnum --port 0 ";
     }
     $flags .= "--srcdir \"$srcdir\"";
 
@@ -1538,6 +1540,12 @@
         return (0,0);
     }
 
+    # where is it?
+    my $port;
+    if(!$port_or_path) {
+        $port = $port_or_path = pidfromfile($portfile);
+    }
+
     # Server is up. Verify that we can speak to it.
     my $pid3 = verifyserver($proto, $ipvnum, $idnum, $ip, $port_or_path);
     if(!$pid3) {
@@ -1556,7 +1564,7 @@
 
     sleep(1);
 
-    return ($httppid, $pid2);
+    return ($httppid, $pid2, $port);
 }
 
 #######################################################################
@@ -4611,8 +4619,8 @@
                 stopserver('gopher');
             }
             if(!$run{'gopher'}) {
-                ($pid, $pid2) = runhttpserver("gopher", $verbose, 0,
-                                              $GOPHERPORT);
+                ($pid, $pid2, $GOPHERPORT) =
+                    runhttpserver("gopher", $verbose, 0);
                 if($pid <= 0) {
                     return "failed starting GOPHER server";
                 }
@@ -4628,8 +4636,8 @@
                 stopserver('gopher-ipv6');
             }
             if(!$run{'gopher-ipv6'}) {
-                ($pid, $pid2) = runhttpserver("gopher", $verbose, "ipv6",
-                                              $GOPHER6PORT);
+                ($pid, $pid2, $GOPHER6PORT) =
+                    runhttpserver("gopher", $verbose, "ipv6");
                 if($pid <= 0) {
                     return "failed starting GOPHER-IPv6 server";
                 }
@@ -4655,8 +4663,8 @@
                 stopserver('http');
             }
             if(!$run{'http'}) {
-                ($pid, $pid2) = runhttpserver("http", $verbose, 0,
-                                              $HTTPPORT);
+                ($pid, $pid2, $HTTPPORT) =
+                    runhttpserver("http", $verbose, 0);
                 if($pid <= 0) {
                     return "failed starting HTTP server";
                 }
@@ -4672,8 +4680,8 @@
                 stopserver('http-proxy');
             }
             if(!$run{'http-proxy'}) {
-                ($pid, $pid2) = runhttpserver("http", $verbose, "proxy",
-                                              $HTTPPROXYPORT);
+                ($pid, $pid2, $HTTPPROXYPORT) =
+                    runhttpserver("http", $verbose, "proxy");
                 if($pid <= 0) {
                     return "failed starting HTTP-proxy server";
                 }
@@ -4688,8 +4696,8 @@
                 stopserver('http-ipv6');
             }
             if(!$run{'http-ipv6'}) {
-                ($pid, $pid2) = runhttpserver("http", $verbose, "ipv6",
-                                              $HTTP6PORT);
+                ($pid, $pid2, $HTTP6PORT) =
+                    runhttpserver("http", $verbose, "ipv6");
                 if($pid <= 0) {
                     return "failed starting HTTP-IPv6 server";
                 }
@@ -4775,8 +4783,8 @@
                 stopserver('http');
             }
             if(!$run{'http'}) {
-                ($pid, $pid2) = runhttpserver("http", $verbose, 0,
-                                              $HTTPPORT);
+                ($pid, $pid2, $HTTPPORT) =
+                    runhttpserver("http", $verbose, 0);
                 if($pid <= 0) {
                     return "failed starting HTTP server";
                 }
@@ -4895,8 +4903,9 @@
                 stopserver('http-unix');
             }
             if(!$run{'http-unix'}) {
-                ($pid, $pid2) = runhttpserver("http", $verbose, "unix",
-                                              $HTTPUNIXPATH);
+                my $unused;
+                ($pid, $pid2, $unused) =
+                    runhttpserver("http", $verbose, "unix", $HTTPUNIXPATH);
                 if($pid <= 0) {
                     return "failed starting HTTP-unix server";
                 }
@@ -5427,11 +5436,9 @@
 
 $minport         = $base; # original base port number
 
-$HTTPPORT        = $base++; # HTTP server port
 $HTTPSPORT       = $base++; # HTTPS (stunnel) server port
 $FTPPORT         = $base++; # FTP server port
 $FTPSPORT        = $base++; # FTPS (stunnel) server port
-$HTTP6PORT       = $base++; # HTTP IPv6 server port
 $FTP2PORT        = $base++; # FTP server 2 port
 $FTP6PORT        = $base++; # FTP IPv6 port
 $TFTPPORT        = $base++; # TFTP (UDP) port
@@ -5446,11 +5453,8 @@
 $SMTP6PORT       = $base++; # SMTP IPv6 server port
 $RTSPPORT        = $base++; # RTSP server port
 $RTSP6PORT       = $base++; # RTSP IPv6 server port
-$GOPHERPORT      = $base++; # Gopher IPv4 server port
-$GOPHER6PORT     = $base++; # Gopher IPv6 server port
 $HTTPTLSPORT     = $base++; # HTTP TLS (non-stunnel) server port
 $HTTPTLS6PORT    = $base++; # HTTP TLS (non-stunnel) IPv6 server port
-$HTTPPROXYPORT   = $base++; # HTTP proxy port, when using CONNECT
 $HTTP2PORT       = $base++; # HTTP/2 port
 $DICTPORT        = $base++; # DICT port
 $SMBPORT         = $base++; # SMB port
diff --git a/tests/server/sws.c b/tests/server/sws.c
index 427bd6e..faa1143 100644
--- a/tests/server/sws.c
+++ b/tests/server/sws.c
@@ -1849,6 +1849,7 @@
   bool unlink_socket = false;
 #endif
   const char *pidname = ".http.pid";
+  const char *portname = ".http.port";
   struct httprequest req;
   int rc = 0;
   int error;
@@ -1881,6 +1882,11 @@
       if(argc>arg)
         pidname = argv[arg++];
     }
+    else if(!strcmp("--portfile", argv[arg])) {
+      arg++;
+      if(argc>arg)
+        portname = argv[arg++];
+    }
     else if(!strcmp("--logfile", argv[arg])) {
       arg++;
       if(argc>arg)
@@ -1928,7 +1934,7 @@
         char *endptr;
         unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
         if((endptr != argv[arg] + strlen(argv[arg])) ||
-           (ulnum < 1025UL) || (ulnum > 65535UL)) {
+           (ulnum && ((ulnum < 1025UL) || (ulnum > 65535UL)))) {
           fprintf(stderr, "sws: invalid --port argument (%s)\n",
                   argv[arg]);
           return 0;
@@ -1961,6 +1967,7 @@
            " --version\n"
            " --logfile [file]\n"
            " --pidfile [file]\n"
+           " --portfile [file]\n"
            " --ipv4\n"
            " --ipv6\n"
            " --unix-socket [file]\n"
@@ -1972,8 +1979,6 @@
     }
   }
 
-  msnprintf(port_str, sizeof(port_str), "port %hu", port);
-
 #ifdef WIN32
   win32_init();
   atexit(win32_cleanup);
@@ -2080,11 +2085,58 @@
   }
   if(0 != rc) {
     error = SOCKERRNO;
-    logmsg("Error binding socket on %s: (%d) %s",
-           location_str, error, strerror(error));
+    logmsg("Error binding socket: (%d) %s", error, strerror(error));
     goto sws_cleanup;
   }
 
+  if(!port) {
+    /* The system was supposed to choose a port number, figure out which
+       port we actually got and update the listener port value with it. */
+    curl_socklen_t la_size;
+    srvr_sockaddr_union_t localaddr;
+#ifdef ENABLE_IPV6
+    if(socket_domain != AF_INET6)
+#endif
+      la_size = sizeof(localaddr.sa4);
+#ifdef ENABLE_IPV6
+    else
+      la_size = sizeof(localaddr.sa6);
+#endif
+    memset(&localaddr.sa, 0, (size_t)la_size);
+    if(getsockname(sock, &localaddr.sa, &la_size) < 0) {
+      error = SOCKERRNO;
+      logmsg("getsockname() failed with error: (%d) %s",
+             error, strerror(error));
+      sclose(sock);
+      goto sws_cleanup;
+    }
+    switch(localaddr.sa.sa_family) {
+    case AF_INET:
+      port = ntohs(localaddr.sa4.sin_port);
+      break;
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      port = ntohs(localaddr.sa6.sin6_port);
+      break;
+#endif
+    default:
+      break;
+    }
+    if(!port) {
+      /* Real failure, listener port shall not be zero beyond this point. */
+      logmsg("Apparently getsockname() succeeded, with listener port zero.");
+      logmsg("A valid reason for this failure is a binary built without");
+      logmsg("proper network library linkage. This might not be the only");
+      logmsg("reason, but double check it before anything else.");
+      sclose(sock);
+      goto sws_cleanup;
+    }
+  }
+#ifdef USE_UNIX_SOCKETS
+  if(socket_domain != AF_UNIX)
+#endif
+    msnprintf(port_str, sizeof(port_str), "port %hu", port);
+
   logmsg("Running %s %s version on %s",
          use_gopher?"GOPHER":"HTTP", socket_type, location_str);
 
@@ -2111,6 +2163,10 @@
   if(!wrotepidfile)
     goto sws_cleanup;
 
+  wrotepidfile = write_portfile(portname, port);
+  if(!wrotepidfile)
+    goto sws_cleanup;
+
   /* initialization of httprequest struct is done before get_request(), but
      the pipelining struct field must be initialized previously to FALSE
      every time a new connection arrives. */