diff --git a/mac/Sources/Byre/Tailnet.swift b/mac/Sources/Byre/Tailnet.swift
index e8fad82..5992d6f 100644
--- a/mac/Sources/Byre/Tailnet.swift
+++ b/mac/Sources/Byre/Tailnet.swift
@@ -191,10 +191,14 @@ final class Tailnet {
 
     private func discover() async {
         while true {
-            guard running else {
+            guard running, !peers.isEmpty else {
                 try? await Task.sleep(for: .milliseconds(500))
                 continue
             }
+            for origin in Servers.shared.origins where !peers.contains(URL(string: origin)!.host()!.lowercased()) {
+                log.notice("forgetting \(origin, privacy: .public), which left the tailnet")
+                Servers.shared.remove(origin)
+            }
             let candidates = servers.filter { !Servers.shared.origins.contains($0.absoluteString) }
             let found = await withTaskGroup(of: URL?.self) { group in
                 for origin in candidates {