From 48fbe93e726cf0b2912e2aea9c88c056889107e4 Mon Sep 17 00:00:00 2001
From: Christina Wen <37028905+c22wen@users.noreply.github.com>
Date: Wed, 16 Sep 2020 11:54:00 -0400
Subject: [PATCH] wgengine/magicsock: clarify pre-disco 'tailscale ping' error
 message

This change clarifies the error message when a user pings a peer that is using an outdated version of Tailscale.
---
 wgengine/magicsock/magicsock.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go
index 6ab027771..fa4daf94b 100644
--- a/wgengine/magicsock/magicsock.go
+++ b/wgengine/magicsock/magicsock.go
@@ -648,8 +648,8 @@ func (c *Conn) Ping(ip netaddr.IP, cb func(*ipnstate.PingResult)) {
 	}
 
 	dk, ok := c.discoOfNode[peer.Key]
-	if !ok {
-		res.Err = "no discovery key for peer (pre 0.100?)"
+	if !ok { // peer is using outdated Tailscale version (pre-0.100)
+		res.Err = "no discovery key for peer (pre Tailscale 0.100 version?). Try: ping 100.x.y.z"
 		cb(res)
 		return
 	}