diff --git a/Changes.rst b/Changes.rst
index b2278ab..fa0fb22 100644
--- a/Changes.rst
+++ b/Changes.rst
@@ -23,11 +23,12 @@
 ``persist-key`` option has been enabled by default.
     All the keys will be kept in memory across restart.
 
-Default for ``--topology`` changed to ``subnet``
-    Previous releases used ``net30`` as default. This only affects
-    configs with ``--dev tun`` and only IPv4. Note that this
-    changes the semantics of ``--ifconfig``, so if you have manual
-    settings for that in your config but not set ``--topology``
+Default for ``--topology`` changed to ``subnet`` for ``--mode server``
+    Previous releases always used ``net30`` as default. This only affects
+    configs with ``--mode server`` or ``--server`` (the latter implies the
+    former), and ``--dev tun``, and only if IPv4 is enabled.
+    Note that this changes the semantics of ``--ifconfig``, so if you have
+    manual settings for that in your config but not set ``--topology``
     your config might fail to parse with the new version. Just adding
     ``--topology net30`` to the config should fix the problem.
     By default ``--topology`` is pushed from server to client.
diff --git a/src/openvpn/helper.c b/src/openvpn/helper.c
index 1bab84c..5681718 100644
--- a/src/openvpn/helper.c
+++ b/src/openvpn/helper.c
@@ -137,6 +137,32 @@
 }
 
 
+/**
+ * Set --topology default depending on --mode
+ */
+void
+helper_setdefault_topology(struct options *o)
+{
+    if (o->topology != TOP_UNDEF)
+    {
+        return;
+    }
+    int dev = dev_type_enum(o->dev, o->dev_type);
+    if (dev != DEV_TYPE_TUN)
+    {
+        return;
+    }
+    if (o->mode == MODE_SERVER)
+    {
+        o->topology = TOP_SUBNET;
+    }
+    else
+    {
+        o->topology = TOP_NET30;
+    }
+}
+
+
 /*
  * Process server, server-bridge, and client helper
  * directives after the parameters themselves have been
@@ -151,7 +177,6 @@
      * Get tun/tap/null device type
      */
     const int dev = dev_type_enum(o->dev, o->dev_type);
-    const int topology = o->topology;
 
     /*
      *
@@ -177,11 +202,11 @@
 
         if (o->server_flags & SF_NOPOOL)
         {
-            msg( M_USAGE, "--server-ipv6 is incompatible with 'nopool' option" );
+            msg(M_USAGE, "--server-ipv6 is incompatible with 'nopool' option");
         }
         if (o->ifconfig_ipv6_pool_defined)
         {
-            msg( M_USAGE, "--server-ipv6 already defines an ifconfig-ipv6-pool, so you can't also specify --ifconfig-pool explicitly");
+            msg(M_USAGE, "--server-ipv6 already defines an ifconfig-ipv6-pool, so you can't also specify --ifconfig-pool explicitly");
         }
 
         o->mode = MODE_SERVER;
@@ -207,7 +232,7 @@
                                                   o->server_netbits_ipv6 < 112 ? 0x1000 : 2);
         o->ifconfig_ipv6_pool_netbits = o->server_netbits_ipv6;
 
-        push_option( o, "tun-ipv6", M_USAGE );
+        push_option(o, "tun-ipv6", M_USAGE);
     }
 
     /*
@@ -305,8 +330,10 @@
 
             o->mode = MODE_SERVER;
             o->tls_server = true;
+            /* Need to know topology now */
+            helper_setdefault_topology(o);
 
-            if (topology == TOP_NET30 || topology == TOP_P2P)
+            if (o->topology == TOP_NET30 || o->topology == TOP_P2P)
             {
                 o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);
                 o->ifconfig_remote_netmask = print_in_addr_t(o->server_network + 2, 0, &o->gc);
@@ -324,12 +351,12 @@
                 {
                     push_option(o, print_opt_route(o->server_network, o->server_netmask, &o->gc), M_USAGE);
                 }
-                else if (topology == TOP_NET30)
+                else if (o->topology == TOP_NET30)
                 {
                     push_option(o, print_opt_route(o->server_network + 1, 0, &o->gc), M_USAGE);
                 }
             }
-            else if (topology == TOP_SUBNET)
+            else if (o->topology == TOP_SUBNET)
             {
                 o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);
                 o->ifconfig_remote_netmask = print_in_addr_t(o->server_netmask, 0, &o->gc);
@@ -354,9 +381,9 @@
                 ASSERT(0);
             }
 
-            push_option(o, print_opt_topology(topology, &o->gc), M_USAGE);
+            push_option(o, print_opt_topology(o->topology, &o->gc), M_USAGE);
 
-            if (topology == TOP_NET30 && !(o->server_flags & SF_NOPOOL))
+            if (o->topology == TOP_NET30 && !(o->server_flags & SF_NOPOOL))
             {
                 msg(M_WARN, "WARNING: --topology net30 support for server "
                     "configs with IPv4 pools will be removed in a future "
@@ -394,7 +421,7 @@
         }
 
         /* set push-ifconfig-constraint directive */
-        if ((dev == DEV_TYPE_TAP || topology == TOP_SUBNET))
+        if ((dev == DEV_TYPE_TAP || o->topology == TOP_SUBNET))
         {
             o->push_ifconfig_constraint_defined = true;
             o->push_ifconfig_constraint_network = o->server_network;
diff --git a/src/openvpn/helper.h b/src/openvpn/helper.h
index d0fd17d..6b42e13 100644
--- a/src/openvpn/helper.h
+++ b/src/openvpn/helper.h
@@ -30,6 +30,8 @@
 
 #include "options.h"
 
+void helper_setdefault_topology(struct options *o);
+
 void helper_keepalive(struct options *o);
 
 void helper_client_server(struct options *o);
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index e2bfe0e..07387cd 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -796,7 +796,7 @@
         o->gc_owned = true;
     }
     o->mode = MODE_POINT_TO_POINT;
-    o->topology = TOP_SUBNET;
+    o->topology = TOP_UNDEF;
     o->ce.proto = PROTO_UDP;
     o->ce.af = AF_UNSPEC;
     o->ce.bind_ipv6_only = false;
@@ -3478,6 +3478,7 @@
     }
 }
 
+
 /**
  * Checks for availibility of Chacha20-Poly1305 and sets
  * the ncp_cipher to either AES-256-GCM:AES-128-GCM or
@@ -3680,6 +3681,8 @@
      * sequences of options.
      */
     helper_client_server(o);
+    /* must be called after helpers that might set --mode */
+    helper_setdefault_topology(o);
     helper_keepalive(o);
     helper_tcp_nodelay(o);