diff --git a/Cargo.lock b/Cargo.lock
index c504b94..fc30027 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -382,6 +382,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "crc32fast"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b540bd8bc810d3885c6ea91e2018302f68baba2129ab3e88f32389ee9370880d"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
 [[package]]
 name = "crossbeam-channel"
 version = "0.3.9"
@@ -614,6 +623,16 @@ dependencies = [
  "rustc_version",
 ]
 
+[[package]]
+name = "flate2"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f82b0f4c27ad9f8bfd1f3208d882da2b09c301bc1c828fd3a00d0216d2fbbff6"
+dependencies = [
+ "crc32fast",
+ "miniz_oxide",
+]
+
 [[package]]
 name = "futures-channel"
 version = "0.3.21"
@@ -1098,6 +1117,7 @@ dependencies = [
  "libc",
  "nix 0.17.0",
  "posix-acl",
+ "procfs",
  "serde",
  "serde_derive",
  "sodiumoxide",
@@ -1477,6 +1497,21 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "procfs"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0941606b9934e2d98a3677759a971756eb821f75764d0e0d26946d08e74d9104"
+dependencies = [
+ "bitflags",
+ "byteorder",
+ "chrono",
+ "flate2",
+ "hex",
+ "lazy_static",
+ "libc",
+]
+
 [[package]]
 name = "pwhash"
 version = "0.3.1"
@@ -1599,6 +1634,7 @@ version = "0.1.0"
 dependencies = [
  "libcitadel",
  "serde",
+ "serde_repr",
  "zbus",
  "zvariant",
 ]
diff --git a/libcitadel/Cargo.toml b/libcitadel/Cargo.toml
index 8770628..5eb3829 100644
--- a/libcitadel/Cargo.toml
+++ b/libcitadel/Cargo.toml
@@ -18,6 +18,7 @@ bincode = "1.2"
 walkdir = "2"
 dbus = "0.6"
 posix-acl = "1.0.0"
+procfs = "0.12.0"
 
 [dependencies.inotify]
 version = "0.8"
diff --git a/realm-config-ui/src/realmsd.rs b/realm-config-ui/src/realmsd.rs
index 1f14b4e..710678e 100644
--- a/realm-config-ui/src/realmsd.rs
+++ b/realm-config-ui/src/realmsd.rs
@@ -12,7 +12,7 @@ pub struct RealmItem {
     name: String,
     description: String,
     realmfs: String,
-    namespace: String,
+    namespace: u64,
     status: u8,
 }
 
diff --git a/realmsd/Cargo.toml b/realmsd/Cargo.toml
index 3054e37..a43574e 100644
--- a/realmsd/Cargo.toml
+++ b/realmsd/Cargo.toml
@@ -9,4 +9,5 @@ libcitadel = { path = "../libcitadel" }
 zbus = "=2.0.0-beta.5"
 zvariant = "2.7.0"
 serde = { version = "1.0", features = ["derive"] }
+serde_repr = "0.1.8"
 
diff --git a/realmsd/src/events.rs b/realmsd/src/events.rs
index 7083fb1..20ff44d 100644
--- a/realmsd/src/events.rs
+++ b/realmsd/src/events.rs
@@ -38,9 +38,9 @@ impl EventHandler {
     }
 
     fn on_started(&self, realm: &Realm) -> zbus::Result<()> {
-        let namespace = realm.pid_namespace().unwrap_or(String::new());
+        let pid_ns = realm.pid_ns().unwrap_or(0);
         let status = realm_status(realm);
-        self.with_server(|server| server.realm_started(realm.name(), namespace.as_str(), status))
+        self.with_server(|server| server.realm_started(realm.name(), pid_ns, status))
     }
 
     fn on_stopped(&self, realm: &Realm) -> zbus::Result<()> {
diff --git a/realmsd/src/realms_manager.rs b/realmsd/src/realms_manager.rs
index e4ddda6..be2ce02 100644
--- a/realmsd/src/realms_manager.rs
+++ b/realmsd/src/realms_manager.rs
@@ -1,15 +1,41 @@
-use libcitadel::{RealmManager, Realm, OverlayType, Result};
+use libcitadel::{RealmManager, Realm, OverlayType, Result, PidLookupResult};
 use std::sync::Arc;
 use zbus::{dbus_interface, ObjectServer,Connection};
 use zvariant::derive::Type;
 use std::thread;
 use std::collections::HashMap;
 use serde::{Serialize,Deserialize};
+use serde_repr::Serialize_repr;
 use crate::events::EventHandler;
 use libcitadel::terminal::Base16Scheme;
 
 pub const REALMS_SERVER_OBJECT_PATH: &str = "/com/subgraph/realms";
 
+#[derive(Serialize_repr, Type, Debug, PartialEq)]
+#[repr(u32)]
+pub enum PidLookupResultCode {
+    Unknown = 1,
+    Realm   = 2,
+    Citadel = 3,
+}
+
+#[derive(Debug, Type, Serialize)]
+pub struct RealmFromCitadelPid {
+    code: PidLookupResultCode,
+    realm: String,
+}
+
+impl From<PidLookupResult> for RealmFromCitadelPid {
+    fn from(result: PidLookupResult) -> Self {
+        match result {
+            PidLookupResult::Unknown => RealmFromCitadelPid { code: PidLookupResultCode::Unknown, realm: String::new() },
+            PidLookupResult::Realm(realm) => RealmFromCitadelPid { code: PidLookupResultCode::Realm, realm: realm.name().to_string() },
+            PidLookupResult::Citadel => RealmFromCitadelPid { code: PidLookupResultCode::Citadel, realm: String::new() },
+        }
+    }
+}
+
+
 #[derive(Clone)]
 pub struct RealmsManagerServer {
     manager: Arc<RealmManager>,
@@ -223,11 +249,8 @@ impl RealmsManagerServer {
         });
     }
 
-    fn realm_from_citadel_pid(&self, pid: u32) -> String {
-        match self.manager.realm_by_pid(pid) {
-            Some(r) => r.name().to_string(),
-            None => String::new(),
-        }
+    fn realm_from_citadel_pid(&self, pid: u32) -> RealmFromCitadelPid {
+        self.manager.realm_by_pid(pid).into()
     }
 
     fn realm_config(&self, name: &str) -> RealmConfig {
@@ -277,7 +300,7 @@ impl RealmsManagerServer {
     }
 
     #[dbus_interface(signal)]
-    pub fn realm_started(&self, realm: &str, namespace: &str, status: u8) -> zbus::Result<()> { Ok(()) }
+    pub fn realm_started(&self, realm: &str, pid_ns: u64, status: u8) -> zbus::Result<()> { Ok(()) }
 
     #[dbus_interface(signal)]
     pub fn realm_stopped(&self, realm: &str, status: u8) -> zbus::Result<()> { Ok(()) }
@@ -319,7 +342,7 @@ struct RealmItem {
     name: String,
     description: String,
     realmfs: String,
-    namespace: String,
+    pid_ns: u64,
     status: u8,
 }
 
@@ -328,9 +351,9 @@ impl RealmItem {
         let name = realm.name().to_string();
         let description = realm.notes().unwrap_or(String::new());
         let realmfs = realm.config().realmfs().to_string();
-        let namespace = realm.pid_namespace().unwrap_or(String::new());
+        let pid_ns = realm.pid_ns().unwrap_or_default();
         let status = realm_status(realm);
-        RealmItem { name, description, realmfs, namespace, status }
+        RealmItem { name, description, realmfs, pid_ns, status }
     }
 }