diff --git a/hostinfo/hostinfo.go b/hostinfo/hostinfo.go
index afb465ece..3e8f2f994 100644
--- a/hostinfo/hostinfo.go
+++ b/hostinfo/hostinfo.go
@@ -43,7 +43,7 @@ func RegisterHostinfoNewHook(f func(*tailcfg.Hostinfo)) {
 
 // New returns a partially populated Hostinfo for the current host.
 func New() *tailcfg.Hostinfo {
-	hostname, _ := os.Hostname()
+	hostname, _ := Hostname()
 	hostname = dnsname.FirstLabel(hostname)
 	hi := &tailcfg.Hostinfo{
 		IPNVersion:      version.Long(),
@@ -509,3 +509,21 @@ func IsInVM86() bool {
 		return New().DeviceModel == copyV86DeviceModel
 	})
 }
+
+type hostnameQuery func() (string, error)
+
+var hostnameFn atomic.Value // of func() (string, error)
+
+// SetHostNameFn sets a custom function for querying the system hostname.
+func SetHostnameFn(fn hostnameQuery) {
+	hostnameFn.Store(fn)
+}
+
+// Hostname returns the system hostname using the function
+// set by SetHostNameFn.  We will fallback to os.Hostname.
+func Hostname() (string, error) {
+	if fn, ok := hostnameFn.Load().(hostnameQuery); ok && fn != nil {
+		return fn()
+	}
+	return os.Hostname()
+}
diff --git a/hostinfo/hostinfo_test.go b/hostinfo/hostinfo_test.go
index 9fe32e044..15b6971b6 100644
--- a/hostinfo/hostinfo_test.go
+++ b/hostinfo/hostinfo_test.go
@@ -5,6 +5,7 @@ package hostinfo
 
 import (
 	"encoding/json"
+	"os"
 	"strings"
 	"testing"
 )
@@ -49,3 +50,31 @@ func TestEtcAptSourceFileIsDisabled(t *testing.T) {
 		})
 	}
 }
+
+func TestCustomHostnameFunc(t *testing.T) {
+	want := "custom-hostname"
+	SetHostnameFn(func() (string, error) {
+		return want, nil
+	})
+
+	got, err := Hostname()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+
+	SetHostnameFn(os.Hostname)
+	got, err = Hostname()
+	want, _ = os.Hostname()
+
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+
+}
diff --git a/ipn/ipnlocal/local.go b/ipn/ipnlocal/local.go
index 9ec4b4767..e21403fbe 100644
--- a/ipn/ipnlocal/local.go
+++ b/ipn/ipnlocal/local.go
@@ -1245,7 +1245,7 @@ func (b *LocalBackend) UpdateStatus(sb *ipnstate.StatusBuilder) {
 			}
 
 		} else {
-			ss.HostName, _ = os.Hostname()
+			ss.HostName, _ = hostinfo.Hostname()
 		}
 		for _, pln := range b.peerAPIListeners {
 			ss.PeerAPIURL = append(ss.PeerAPIURL, pln.urlStr)