diff --git a/ipn/ipnlocal/ssh.go b/ipn/ipnlocal/ssh.go
index 010f8f259..10b2de3f2 100644
--- a/ipn/ipnlocal/ssh.go
+++ b/ipn/ipnlocal/ssh.go
@@ -25,12 +25,9 @@ import (
 	"sync"
 
 	"github.com/tailscale/golang-x-crypto/ssh"
-	"tailscale.com/envknob"
 	"tailscale.com/util/mak"
 )
 
-var useHostKeys = envknob.Bool("TS_USE_SYSTEM_SSH_HOST_KEYS")
-
 // keyTypes are the SSH key types that we either try to read from the
 // system's OpenSSH keys or try to generate for ourselves when not
 // running as root.