diff --git a/splunklib/binding.py b/splunklib/binding.py
index 327d4fed..a4458c66 100644
--- a/splunklib/binding.py
+++ b/splunklib/binding.py
@@ -1457,7 +1457,7 @@ def request(url, message, **kwargs):
         body = message.get("body", "")
         head = {
             "Content-Length": str(len(body)),
-            "Host": host,
+            "Host": "%s:%d" % (host, port),
             "User-Agent": "splunk-sdk-python/%s" % __version__,
             "Accept": "*/*",
             "Connection": "Close",