diff --git a/changelogs/fragments/451_firewall_fix_protocol_parameter.yml b/changelogs/fragments/451_firewall_fix_protocol_parameter.yml
new file mode 100644
index 0000000..9dfc6bd
--- /dev/null
+++ b/changelogs/fragments/451_firewall_fix_protocol_parameter.yml
@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - firewall - Fix issue where opening a specific port resulted in opening the whole protocol of the specified port
diff --git a/plugins/modules/firewalld.py b/plugins/modules/firewalld.py
index 3546749..cf55e1c 100644
--- a/plugins/modules/firewalld.py
+++ b/plugins/modules/firewalld.py
@@ -856,15 +856,16 @@ def main():
     zone = module.params['zone']
     target = module.params['target']
 
+    port = None
     if module.params['port'] is not None:
         if '/' in module.params['port']:
-            port, protocol = module.params['port'].strip().split('/')
+            port, port_protocol = module.params['port'].strip().split('/')
         else:
-            protocol = None
-        if not protocol:
+            port_protocol = None
+        if not port_protocol:
             module.fail_json(msg='improper port format (missing protocol?)')
     else:
-        port = None
+        port_protocol = None
 
     port_forward_toaddr = ''
     port_forward = None
@@ -981,7 +982,7 @@ def main():
 
         transaction = PortTransaction(
             module,
-            action_args=(port, protocol, timeout),
+            action_args=(port, port_protocol, timeout),
             zone=zone,
             desired_state=desired_state,
             permanent=permanent,
@@ -993,7 +994,7 @@ def main():
         if changed is True:
             msgs.append(
                 "Changed port %s to %s" % (
-                    "%s/%s" % (port, protocol), desired_state
+                    "%s/%s" % (port, port_protocol), desired_state
                 )
             )