diff --git a/modules/auxiliary/scanner/portscan/syn.rb b/modules/auxiliary/scanner/portscan/syn.rb
index 887c5f72d2..4400020163 100644
--- a/modules/auxiliary/scanner/portscan/syn.rb
+++ b/modules/auxiliary/scanner/portscan/syn.rb
@@ -102,7 +102,7 @@ class Metasploit3 < Msf::Auxiliary
 		p.ip_saddr = shost
 		p.ip_daddr = dhost
 		p.tcp_sport = sport
-		n.l4.ack = 0
+		p.tcp_flags.ack = 0
 		p.tcp_flags.syn = 1
 		p.tcp_dport = dport
 		p.tcp_win = 3072