diff --git a/FAQ.md b/FAQ.md
index b142408e..974d85ca 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -368,6 +368,11 @@ On most devices, NetGuard will keep running in the background with its foregroun
 On some devices (in particular some Samsung models), where there are lots of applications competing for memory, Android may still stop NetGuard as a last resort.
 Unfortunately this cannot be fixed from NetGuard, and can be considered a shortcoming of the device and/or as a bug in Android.
 
+<a name="FAQ39"></a>
+**(39) How does a VPN based firewall differ from a iptables based firewall?**
+
+See this [Stack Exchange question](http://android.stackexchange.com/questions/152087/any-security-difference-between-root-based-firewall-afwall-and-non-root-based).
+
 <br />
 
 **If you didn't find the answer to your question, you can ask your questions [in this forum](http://forum.xda-developers.com/showthread.php?t=3233012) or contact me directly [by e-mail](mailto:marcel+netguard@faircode.eu)**.
diff --git a/README.md b/README.md
index df48bb2c..bfa8dd77 100644
--- a/README.md
+++ b/README.md
@@ -183,6 +183,9 @@ Frequently Asked Questions (FAQ)
 <a name="FAQ38"></a>
 [**(38) Why did NetGuard stop running?**](https://github.com/M66B/NetGuard/blob/master/FAQ.md#FAQ38)
 
+<a name="FAQ39"></a>
+[**(39) How does a VPN based firewall differ from a iptables based firewall?**](https://github.com/M66B/NetGuard/blob/master/FAQ.md#FAQ39)
+
 Permissions
 -----------