From e2eaae8224faf5ba2e5ae494e9ee357a60af2799 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Mon, 19 Jul 2021 07:52:55 -0700
Subject: [PATCH] cmd/derpprobe: add in a delay to wait for mesh info to sync

---
 cmd/derpprobe/derpprobe.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/cmd/derpprobe/derpprobe.go b/cmd/derpprobe/derpprobe.go
index 363d4983d..c0e11a9e6 100644
--- a/cmd/derpprobe/derpprobe.go
+++ b/cmd/derpprobe/derpprobe.go
@@ -211,6 +211,13 @@ func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.D
 	}
 	defer toc.Close()
 
+	// Wait a bit for from's node to hear about to existing on the
+	// other node in the region, in the case where the two nodes
+	// are different.
+	if from.Name != to.Name {
+		time.Sleep(100 * time.Millisecond) // pretty arbitrary
+	}
+
 	// Make a random packet
 	pkt := make([]byte, 8)
 	crand.Read(pkt)