diff --git a/common.go b/common.go
index c6eec00..d4bea47 100644
--- a/common.go
+++ b/common.go
@@ -45,6 +45,9 @@ func serviceAndRegion(host string) (service string, region string) {
 			service = parts[0]
 			region = parts[1]
 		}
+	} else if len(parts) == 5 {
+		service = parts[2]
+		region = parts[1]
 	} else {
 		// Either service.amazonaws.com or s3-region.amazonaws.com
 		if strings.HasPrefix(parts[0], "s3-") {
diff --git a/sign4.go b/sign4.go
index b5f3e59..89770bd 100644
--- a/sign4.go
+++ b/sign4.go
@@ -33,6 +33,16 @@ func hashedCanonicalRequestV4(request *http.Request, meta *metadata) string {
 	var headersToSign string
 	for _, key := range sortedHeaderKeys {
 		value := strings.TrimSpace(request.Header.Get(key))
+		if key == "host" {
+			//AWS does not include port in signing request.
+			if strings.Contains(value, ":") {
+				split := strings.Split(value, ":")
+				port := split[1]
+				if port == "80" || port == "443" {
+					value = split[0]
+				}
+			}
+		}
 		headersToSign += key + ":" + value + "\n"
 	}
 	meta.signedHeaders = concat(";", sortedHeaderKeys...)