diff --git a/core/posix.hh b/core/posix.hh
index eb8a6a7686..433def40b4 100644
--- a/core/posix.hh
+++ b/core/posix.hh
@@ -196,6 +196,13 @@ public:
         auto r = ::bind(_fd, &sa, sl);
         throw_system_error_on(r == -1);
     }
+    void connect(sockaddr& sa, socklen_t sl) {
+        auto r = ::connect(_fd, &sa, sl);
+        if (r == -1 && errno == EINPROGRESS) {
+            return;
+        }
+        throw_system_error_on(r == -1);
+    }
     socket_address get_address() {
         socket_address addr;
         auto len = (socklen_t) sizeof(addr.u.sas);