diff --git a/network.h b/network.h
index 107e72c8..85c5a6d9 100644
--- a/network.h
+++ b/network.h
@@ -78,6 +78,13 @@ struct PlugVtable {
      *    proxied through. This will typically be a wodge of
      *    standard-error output from a local proxy command, so the
      *    receiver should probably prefix it to indicate this.
+     *
+     * Note that sometimes log messages may be sent even to Socket
+     * types that don't involve making an outgoing connection, e.g.
+     * because the same core implementation (such as Windows handle
+     * sockets) is shared between listening and connecting sockets. So
+     * all Plugs must implement this method, even if only to ignore
+     * the logged events.
      */
     void (*closing)
      (Plug *p, const char *error_msg, int error_code, bool calling_back);
@@ -325,6 +332,20 @@ Socket *new_error_socket_consume_string(Plug *plug, char *errmsg);
  */
 extern Plug *const nullplug;
 
+/*
+ * Some trivial no-op plug functions, also in nullplug.c; exposed here
+ * so that other Plug implementations can use them too.
+ *
+ * In particular, nullplug_log is useful to Plugs that don't need to
+ * worry about logging.
+ */
+void nullplug_log(Plug *plug, PlugLogType type, SockAddr *addr,
+                  int port, const char *err_msg, int err_code);
+void nullplug_closing(Plug *plug, const char *error_msg, int error_code,
+                      bool calling_back);
+void nullplug_receive(Plug *plug, int urgent, const char *data, size_t len);
+void nullplug_sent(Plug *plug, size_t bufsize);
+
 /* ----------------------------------------------------------------------
  * Functions defined outside the network code, which have to be
  * declared in this header file rather than the main putty.h because
diff --git a/nullplug.c b/nullplug.c
index 953f0348..380e4b4f 100644
--- a/nullplug.c
+++ b/nullplug.c
@@ -7,27 +7,26 @@
 
 #include "putty.h"
 
-static void nullplug_socket_log(Plug *plug, PlugLogType type, SockAddr *addr,
-                                int port, const char *err_msg, int err_code)
+void nullplug_log(Plug *plug, PlugLogType type, SockAddr *addr,
+                  int port, const char *err_msg, int err_code)
 {
 }
 
-static void nullplug_closing(Plug *plug, const char *error_msg, int error_code,
-                             bool calling_back)
+void nullplug_closing(Plug *plug, const char *error_msg, int error_code,
+                      bool calling_back)
 {
 }
 
-static void nullplug_receive(
-    Plug *plug, int urgent, const char *data, size_t len)
+void nullplug_receive(Plug *plug, int urgent, const char *data, size_t len)
 {
 }
 
-static void nullplug_sent(Plug *plug, size_t bufsize)
+void nullplug_sent(Plug *plug, size_t bufsize)
 {
 }
 
 static const PlugVtable nullplug_plugvt = {
-    .log = nullplug_socket_log,
+    .log = nullplug_log,
     .closing = nullplug_closing,
     .receive = nullplug_receive,
     .sent = nullplug_sent,
diff --git a/pageant.c b/pageant.c
index 8ca9310b..fb0f86e1 100644
--- a/pageant.c
+++ b/pageant.c
@@ -1624,6 +1624,7 @@ static const PlugVtable pageant_connection_plugvt = {
     .closing = pageant_conn_closing,
     .receive = pageant_conn_receive,
     .sent = pageant_conn_sent,
+    .log = nullplug_log,
 };
 
 static int pageant_listen_accepting(Plug *plug,
@@ -1672,6 +1673,7 @@ static int pageant_listen_accepting(Plug *plug,
 static const PlugVtable pageant_listener_plugvt = {
     .closing = pageant_listen_closing,
     .accepting = pageant_listen_accepting,
+    .log = nullplug_log,
 };
 
 struct pageant_listen_state *pageant_listener_new(
diff --git a/ssh/sharing.c b/ssh/sharing.c
index b5da8657..920218de 100644
--- a/ssh/sharing.c
+++ b/ssh/sharing.c
@@ -1905,6 +1905,7 @@ static const PlugVtable ssh_sharing_conn_plugvt = {
     .closing = share_closing,
     .receive = share_receive,
     .sent = share_sent,
+    .log = nullplug_log,
 };
 
 static int share_listen_accepting(Plug *plug,
@@ -2046,6 +2047,7 @@ bool ssh_share_test_for_upstream(const char *host, int port, Conf *conf)
 static const PlugVtable ssh_sharing_listen_plugvt = {
     .closing = share_listen_closing,
     .accepting = share_listen_accepting,
+    .log = nullplug_log,
 };
 
 void ssh_connshare_provide_connlayer(ssh_sharing_state *sharestate,