diff --git a/todo/nmap.txt b/todo/nmap.txt
index e47111a8e..35c323a1d 100644
--- a/todo/nmap.txt
+++ b/todo/nmap.txt
@@ -83,6 +83,9 @@ o Test a hierarchical classifier for IPv6 OS detection. Our classifier
   suspect playing it by ear will be sufficient. Talk to David for more
   of his thinking on this topic.
 
+o Test Ncat's TLS hostname validation using the TLSPretense tool.
+  https://www.isecpartners.com/news-events/news/2012/october/the-lurking-menace-of-broken-tls-validation.aspx
+
 o [INFRASTRUCTURE] Improve our main web server http configuration to
   better handle high load situations and DoS attacks.  As part of
   this, we may have to raise the max client limits.  But then there is