--- a/toolkit/components/telemetry/pingsender/pingsender.cpp
+++ b/toolkit/components/telemetry/pingsender/pingsender.cpp
@@ -16,16 +16,19 @@ using std::ifstream;
 using std::ios;
 using std::string;
 
 namespace PingSender {
 
 const char* kUserAgent = "pingsender/1.0";
 const char* kCustomVersionHeader = "X-PingSender-Version: 1.0";
 const char* kContentEncodingHeader = "Content-Encoding: gzip";
+// The maximum time, in milliseconds, we allow for the connection phase
+// to the server.
+const uint32_t kConnectionTimeoutMs = 30 * 1000;
 
 /**
  * This shared function returns a Date header string for use in HTTP requests.
  * See "RFC 7231, section 7.1.1.2: Date" for its specifications.
  */
 std::string
 GenerateDateHeader()
 {

--- a/toolkit/components/telemetry/pingsender/pingsender_unix_common.cpp
+++ b/toolkit/components/telemetry/pingsender/pingsender_unix_common.cpp
@@ -177,16 +177,19 @@ CurlWrapper::Post(const string& url, con
   easy_setopt(mCurl, CURLOPT_POSTFIELDSIZE, payload.length());
 
   // Set the contents of the POST data
   easy_setopt(mCurl, CURLOPT_POSTFIELDS, payload.c_str());
 
   // Fail if the server returns a 4xx code
   easy_setopt(mCurl, CURLOPT_FAILONERROR, 1);
 
+  // Override the default connection timeout, which is 5 minutes.
+  easy_setopt(mCurl, CURLOPT_CONNECTTIMEOUT_MS, kConnectionTimeoutMs);
+
   // Block until the operation is performend. Ignore the response, if the POST
   // fails we can't do anything about it.
   err = easy_perform(mCurl);
   // Whatever happens, we want to clean up the header memory.
   slist_free_all(headerChunk);
 
   if (err != CURLE_OK) {
     PINGSENDER_LOG("ERROR: Failed to send HTTP request, %s\n",

--- a/toolkit/components/telemetry/pingsender/pingsender_win.cpp
+++ b/toolkit/components/telemetry/pingsender/pingsender_win.cpp
@@ -71,16 +71,26 @@ Post(const string& url, const string& pa
                                         /* lpszProxyBypass */ NULL,
                                         /* dwFlags */ 0));
 
   if (internet.empty()) {
     PINGSENDER_LOG("ERROR: Could not open wininet internet handle\n");
     return false;
   }
 
+  DWORD timeout = static_cast<DWORD>(kConnectionTimeoutMs);
+  bool rv = InternetSetOption(internet.get(),
+                              INTERNET_OPTION_CONNECT_TIMEOUT,
+                              &timeout,
+                              sizeof(timeout));
+  if (!rv) {
+    PINGSENDER_LOG("ERROR: Could not set the connection timeout\n");
+    return false;
+  }
+
   ScopedHInternet connection(InternetConnect(internet.get(),
                                              host, components.nPort,
                                              /* lpszUsername */ NULL,
                                              /* lpszPassword */ NULL,
                                              INTERNET_SERVICE_HTTP,
                                              /* dwFlags */ 0,
                                              /* dwContext */ NULL));
 
@@ -104,21 +114,21 @@ Post(const string& url, const string& pa
   }
 
   // Build a string containing all the headers.
   std::string headers = GenerateDateHeader() + "\r\n";
   headers += kCustomVersionHeader;
   headers += "\r\n";
   headers += kContentEncodingHeader;
 
-  bool rv = HttpSendRequest(request.get(),
-                            headers.c_str(),
-                            -1L,
-                            (LPVOID)payload.c_str(),
-                            payload.size());
+  rv = HttpSendRequest(request.get(),
+                       headers.c_str(),
+                       -1L,
+                       (LPVOID)payload.c_str(),
+                       payload.size());
   if (!rv) {
     PINGSENDER_LOG("ERROR: Could not execute HTTP POST request\n");
     return false;
   }
 
   // HttpSendRequest doesn't fail if we hit an HTTP error, so manually check
   // for errors. Please note that this is not needed on the Linux/MacOS version
   // of the pingsender, as libcurl already automatically fails on HTTP errors.