diff --git a/README.md b/README.md
index 943ad82..786652f 100644
--- a/README.md
+++ b/README.md
@@ -78,6 +78,7 @@ After you did a `make install`, a project consisting of one file can be compiled
 |         4 | Aborted by user               |
 |        10 | Failed to connect             |
 |        11 | Couldn't resolve host         |
+|        12 | Network is unreachable        |
 | 100 - 999 | HTTP status codes             |
 |     65535 | Unknown error                 |
 
diff --git a/src/http_sync.cpp b/src/http_sync.cpp
index 2c886c7..356fb17 100644
--- a/src/http_sync.cpp
+++ b/src/http_sync.cpp
@@ -151,6 +151,11 @@ const std::uint16_t API::http::request_sync(const method &meth,
         {
             ret = 11;
         }
+        else if (std::strncmp(e.what(),
+                              "Network is unreachable", 22) == 0)
+        {
+            ret = 12;
+        }
         else
         {
             cerr << "RUNTIME ERROR: " << e.what() << std::endl;
diff --git a/src/mastodon-cpp.hpp b/src/mastodon-cpp.hpp
index 2e9a82d..9b8e911 100644
--- a/src/mastodon-cpp.hpp
+++ b/src/mastodon-cpp.hpp
@@ -49,8 +49,9 @@ namespace Mastodon
  *  |         2 | Not implemented               |
  *  |         3 | URL changed (HTTP 301 or 308) |
  *  |         4 | Aborted by user               |
-*   |        10 | Failed to connect             |
-*   |        11 | Couldn't resolve host         |
+ *  |        10 | Failed to connect             |
+ *  |        11 | Couldn't resolve host         |
+ *  |        12 | Network is unreachable        |
  *  | 100 - 999 | HTTP status codes             |
  *  |     65535 | Unknown exception             |
  */