diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallAliasCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallAliasCmdlet.cs
index 8275a0e..8b81f87 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallAliasCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallAliasCmdlet.cs
@@ -8,7 +8,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallAlias")]
     [OutputType(typeof(PveFirewallAlias))]
-    public class GetPveFirewallAliasCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallAliasCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -19,7 +19,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = false, HelpMessage = "Optional alias name to filter by.")]
         public string? Name { get; set; }
@@ -40,7 +40,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -51,7 +51,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Getting firewall aliases at level '{level}'...");
             var aliases = service.GetAliases(session, level, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallGroupCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallGroupCmdlet.cs
index 3128d93..cf65456 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallGroupCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallGroupCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallGroup")]
     [OutputType(typeof(PveFirewallGroup), typeof(PveFirewallRule))]
-    public class GetPveFirewallGroupCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallGroupCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = false, Position = 0, HelpMessage = "The security group name. If specified, returns rules within the group.")]
         public string? Group { get; set; }
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetCmdlet.cs
index f1ac250..402bd7e 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetCmdlet.cs
@@ -8,7 +8,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallIpSet")]
     [OutputType(typeof(PveFirewallIpSet))]
-    public class GetPveFirewallIpSetCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallIpSetCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -19,7 +19,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = false, HelpMessage = "Optional IP set name to filter by.")]
         public string? Name { get; set; }
@@ -40,7 +40,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -51,7 +51,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Getting firewall IP sets at level '{level}'...");
             var ipSets = service.GetIpSets(session, level, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetEntryCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetEntryCmdlet.cs
index 822449b..5193e24 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetEntryCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallIpSetEntryCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallIpSetEntry")]
     [OutputType(typeof(PveFirewallIpSetEntry))]
-    public class GetPveFirewallIpSetEntryCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallIpSetEntryCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The IP set name.")]
         public string Name { get; set; } = string.Empty;
@@ -39,7 +39,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -50,7 +50,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Getting entries for IP set '{Name}' at level '{level}'...");
             var entries = service.GetIpSetEntries(session, level, Name, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallOptionsCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallOptionsCmdlet.cs
index f2b91fb..bb01744 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallOptionsCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallOptionsCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallOptions")]
     [OutputType(typeof(PveFirewallOptions))]
-    public class GetPveFirewallOptionsCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallOptionsCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         protected override void ProcessRecord()
         {
@@ -36,7 +36,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -47,7 +47,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Getting firewall options at level '{level}'...");
             var options = service.GetOptions(session, level, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRefCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRefCmdlet.cs
index ce5b87f..e67fc0e 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRefCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRefCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallRef")]
     [OutputType(typeof(PveFirewallRef))]
-    public class GetPveFirewallRefCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallRefCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = false, HelpMessage = "Optional type filter for references.")]
         public string? Type { get; set; }
@@ -39,7 +39,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -50,7 +50,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Getting firewall references at level '{level}'...");
             var refs = service.GetRefs(session, level, Type, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRuleCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRuleCmdlet.cs
index 76e5ad6..6babe06 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRuleCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/GetPveFirewallRuleCmdlet.cs
@@ -8,7 +8,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Get, "PveFirewallRule")]
     [OutputType(typeof(PveFirewallRule))]
-    public class GetPveFirewallRuleCmdlet : PveCmdletBase
+    public sealed class GetPveFirewallRuleCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -19,7 +19,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = false, HelpMessage = "Optional rule position to filter by.")]
         public int? Position { get; set; }
@@ -40,7 +40,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -51,7 +51,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Getting firewall rules at level '{level}'...");
             var rules = service.GetRules(session, level, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallAliasCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallAliasCmdlet.cs
index 1ca6fc8..e8515e3 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallAliasCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallAliasCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.New, "PveFirewallAlias", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class NewPveFirewallAliasCmdlet : PveCmdletBase
+    public sealed class NewPveFirewallAliasCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The alias name.")]
         public string Name { get; set; } = string.Empty;
@@ -45,7 +45,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -59,7 +59,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Creating firewall alias '{Name}' at level '{level}'...");
             service.CreateAlias(session, level, Name, Cidr, Comment, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallGroupCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallGroupCmdlet.cs
index 1f68ba4..47d76ff 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallGroupCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallGroupCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.New, "PveFirewallGroup", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class NewPveFirewallGroupCmdlet : PveCmdletBase
+    public sealed class NewPveFirewallGroupCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The security group name.")]
         public string Group { get; set; } = string.Empty;
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetCmdlet.cs
index a11c282..789a3c3 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.New, "PveFirewallIpSet", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class NewPveFirewallIpSetCmdlet : PveCmdletBase
+    public sealed class NewPveFirewallIpSetCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The IP set name.")]
         public string Name { get; set; } = string.Empty;
@@ -42,7 +42,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -56,7 +56,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Creating firewall IP set '{Name}' at level '{level}'...");
             service.CreateIpSet(session, level, Name, Comment, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetEntryCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetEntryCmdlet.cs
index 19dba6b..eafacf6 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetEntryCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallIpSetEntryCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.New, "PveFirewallIpSetEntry", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class NewPveFirewallIpSetEntryCmdlet : PveCmdletBase
+    public sealed class NewPveFirewallIpSetEntryCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The IP set name.")]
         public string Name { get; set; } = string.Empty;
@@ -48,7 +48,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -62,7 +62,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Adding entry '{Cidr}' to IP set '{Name}' at level '{level}'...");
             service.AddIpSetEntry(session, level, Name, Cidr, NoMatch.IsPresent, Comment, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallRuleCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallRuleCmdlet.cs
index 94c1bf2..203881f 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallRuleCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/NewPveFirewallRuleCmdlet.cs
@@ -8,7 +8,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.New, "PveFirewallRule", SupportsShouldProcess = true)]
     [OutputType(typeof(PveFirewallRule))]
-    public class NewPveFirewallRuleCmdlet : PveCmdletBase
+    public sealed class NewPveFirewallRuleCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -19,7 +19,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The rule type: in, out, or group.")]
         [ValidateSet("in", "out", "group")]
@@ -75,7 +75,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -89,7 +89,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             var config = new Dictionary<string, string>
             {
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallAliasCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallAliasCmdlet.cs
index 6ddc16d..4281744 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallAliasCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallAliasCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Remove, "PveFirewallAlias", SupportsShouldProcess = true, ConfirmImpact = ConfirmImpact.High)]
     [OutputType(typeof(void))]
-    public class RemovePveFirewallAliasCmdlet : PveCmdletBase
+    public sealed class RemovePveFirewallAliasCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The alias name to remove.")]
         public string Name { get; set; } = string.Empty;
@@ -39,7 +39,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -53,7 +53,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Removing firewall alias '{Name}' at level '{level}'...");
             service.RemoveAlias(session, level, Name, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallGroupCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallGroupCmdlet.cs
index 2e24dc2..9b0413f 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallGroupCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallGroupCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Remove, "PveFirewallGroup", SupportsShouldProcess = true, ConfirmImpact = ConfirmImpact.High)]
     [OutputType(typeof(void))]
-    public class RemovePveFirewallGroupCmdlet : PveCmdletBase
+    public sealed class RemovePveFirewallGroupCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The security group name to remove.")]
         public string Group { get; set; } = string.Empty;
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetCmdlet.cs
index a7ae1e3..9e55d1c 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Remove, "PveFirewallIpSet", SupportsShouldProcess = true, ConfirmImpact = ConfirmImpact.High)]
     [OutputType(typeof(void))]
-    public class RemovePveFirewallIpSetCmdlet : PveCmdletBase
+    public sealed class RemovePveFirewallIpSetCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The IP set name to remove.")]
         public string Name { get; set; } = string.Empty;
@@ -39,7 +39,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -53,7 +53,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Removing firewall IP set '{Name}' at level '{level}'...");
             service.RemoveIpSet(session, level, Name, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetEntryCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetEntryCmdlet.cs
index 97da0c6..7b1735a 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetEntryCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallIpSetEntryCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Remove, "PveFirewallIpSetEntry", SupportsShouldProcess = true, ConfirmImpact = ConfirmImpact.High)]
     [OutputType(typeof(void))]
-    public class RemovePveFirewallIpSetEntryCmdlet : PveCmdletBase
+    public sealed class RemovePveFirewallIpSetEntryCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The IP set name.")]
         public string Name { get; set; } = string.Empty;
@@ -42,7 +42,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -56,7 +56,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Removing entry '{Cidr}' from IP set '{Name}' at level '{level}'...");
             service.RemoveIpSetEntry(session, level, Name, Cidr, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallRuleCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallRuleCmdlet.cs
index 5888161..6114f11 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallRuleCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/RemovePveFirewallRuleCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Remove, "PveFirewallRule", SupportsShouldProcess = true, ConfirmImpact = ConfirmImpact.High)]
     [OutputType(typeof(void))]
-    public class RemovePveFirewallRuleCmdlet : PveCmdletBase
+    public sealed class RemovePveFirewallRuleCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The rule position to remove.")]
         public int Position { get; set; }
@@ -39,7 +39,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -53,7 +53,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Removing firewall rule at position {Position} ({level})...");
             service.RemoveRule(session, level, Position, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallAliasCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallAliasCmdlet.cs
index 3eea70e..d2766f1 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallAliasCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallAliasCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Set, "PveFirewallAlias", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class SetPveFirewallAliasCmdlet : PveCmdletBase
+    public sealed class SetPveFirewallAliasCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The alias name to update.")]
         public string Name { get; set; } = string.Empty;
@@ -45,7 +45,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -59,7 +59,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             WriteVerbose($"Updating firewall alias '{Name}' at level '{level}'...");
             service.UpdateAlias(session, level, Name, Cidr, Comment, Node, vmid);
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallIpSetEntryCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallIpSetEntryCmdlet.cs
index d178cc7..49eb4be 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallIpSetEntryCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallIpSetEntryCmdlet.cs
@@ -7,7 +7,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Set, "PveFirewallIpSetEntry", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class SetPveFirewallIpSetEntryCmdlet : PveCmdletBase
+    public sealed class SetPveFirewallIpSetEntryCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -18,7 +18,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The IP set name.")]
         public string Name { get; set; } = string.Empty;
@@ -48,7 +48,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -62,7 +62,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
             bool? nomatch = NoMatch.IsPresent ? true : (bool?)null;
 
             WriteVerbose($"Updating entry '{Cidr}' in IP set '{Name}' at level '{level}'...");
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallOptionsCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallOptionsCmdlet.cs
index 46ae7d7..36fa255 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallOptionsCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallOptionsCmdlet.cs
@@ -8,7 +8,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Set, "PveFirewallOptions", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class SetPveFirewallOptionsCmdlet : PveCmdletBase
+    public sealed class SetPveFirewallOptionsCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -19,7 +19,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = false, HelpMessage = "Enable or disable the firewall.")]
         public SwitchParameter Enable { get; set; }
@@ -66,7 +66,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -80,7 +80,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             var config = new Dictionary<string, string>();
 
diff --git a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallRuleCmdlet.cs b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallRuleCmdlet.cs
index e65bd81..9383e48 100644
--- a/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallRuleCmdlet.cs
+++ b/src/PSProxmoxVE/Cmdlets/Firewall/SetPveFirewallRuleCmdlet.cs
@@ -8,7 +8,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 {
     [Cmdlet(VerbsCommon.Set, "PveFirewallRule", SupportsShouldProcess = true)]
     [OutputType(typeof(void))]
-    public class SetPveFirewallRuleCmdlet : PveCmdletBase
+    public sealed class SetPveFirewallRuleCmdlet : PveCmdletBase
     {
         [Parameter(Mandatory = true, Position = 0, HelpMessage = "The firewall level: Cluster, Node, Vm, or Container.")]
         [ValidateSet("Cluster", "Node", "Vm", "Container")]
@@ -19,7 +19,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
         [Parameter(Mandatory = false, HelpMessage = "The VM/Container ID. Required when Level is Vm or Container.")]
         [ValidateRange(100, 999999999)]
-        public int VmId { get; set; }
+        public int? VmId { get; set; }
 
         [Parameter(Mandatory = true, HelpMessage = "The rule position to update.")]
         public int Position { get; set; }
@@ -78,7 +78,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
             if (string.Equals(level, "Vm", StringComparison.OrdinalIgnoreCase) ||
                 string.Equals(level, "Container", StringComparison.OrdinalIgnoreCase))
             {
-                if (VmId == 0)
+                if (!VmId.HasValue)
                 {
                     ThrowTerminatingError(new ErrorRecord(
                         new PSArgumentException("VmId is required when Level is Vm or Container."),
@@ -92,7 +92,7 @@ namespace PSProxmoxVE.Cmdlets.Firewall
 
             var session = GetSession();
             var service = new FirewallService();
-            int? vmid = VmId > 0 ? VmId : (int?)null;
+            var vmid = VmId;
 
             var config = new Dictionary<string, string>();