diff --git a/content/guides/firewall-testing.md b/content/guides/firewall-testing.md
index ed8d60e..42e591a 100644
--- a/content/guides/firewall-testing.md
+++ b/content/guides/firewall-testing.md
@@ -25,32 +25,28 @@ Testing Tools
 To test your firewall there are a few software tools and a few online
 services to help you. I suggest the following tools:
 
--   [Nessus](http://www.nessus.org) is probably the best open source
-    security scanner available.
-    [Nessus](http://www.nessus.org) not only checks the firewall of a
-    host, but also scans for known application vulnerabilities.
-    I highly recommend [Nessus](http://www.nessus.org) for periodic
-    (weekly, monthly, etc) scans.
--   [Nmap](http://nmap.org/) ("Network Mapper") is an open source
+-   [Nessus](https://www.tenable.com/products/nessus) is probably the best 
+    open source security scanner available.
+    [Nessus](https://www.tenable.com/products/nessus) not only checks the
+    firewall of a host, but also scans for known application vulnerabilities.
+    I highly recommend [Nessus](https://www.tenable.com/products/nessus) for
+    periodic (weekly, monthly, etc) scans.
+-   [Nmap](https://nmap.org/) ("Network Mapper") is an open source
     utility for network exploration or security auditing.
 
 It is also possible to try out connections, see what effect your firewall
 is having and monitor exactly what is happening on the network with tools
 such as:
 
--   [netcat](http://netcat.sourceforge.net/) (`nc`) allows you to easily
+-   [netcat](https://netcat.sourceforge.net/) (`nc`) allows you to easily
     listen for connections and create connections and send data over
     both TCP and UDP.
--   [tcpdump](http://www.tcpdump.org/) allows you to see and capture
+-   [tcpdump](https://www.tcpdump.org/) allows you to see and capture
     the traffic seen by a network device.
 -   [Wireshark](https://www.wireshark.org/) is a GUI equivalent which
     makes it very easy to decode and filter live traffic as well as
     being able to read data captured by `tcpdump`.
 
-Other useful links:
-
--   [Top 125 Network Security Tools](http://sectool.org/)
-
 
 Online Tools
 ------------
@@ -58,23 +54,18 @@ Online Tools
 There are a number of sites that offer firewall testing services to
 everyone:
 
--   [AuditMyPC](http://www.auditmypc.com/)
--   [Security Space](http://www.securityspace.com/sspace/index.html), a
+-   [AuditMyPC](https://www.auditmypc.com/)
+-   [Security Space](https://www.securityspace.com/sspace/index.html), a
     commercial service with a free scan. \
     These people are using something like
-    [Nessus](http://www.nessus.org) if not
-    [Nessus](http://www.nessus.org) itself).
+    [Nessus](https://www.tenable.com/products/nessus) if not
+    [Nessus](https://www.tenable.com/products/nessus) itself).
 -   [Shields UP!!](https://grc.com/x/ne.dll?bh0bkyd2) NanoProbe
     Technology Internet Security Testing for... Windows Users. (note:
     well, it says for Windows, but it is a port scanner with a limited
-    range of ports to be scanned...)
--   [SubnetOnline.com](http://www.subnetonline.com/) provide tools
+    range of ports to be scanned.)
+-   [SubnetOnline.com](https://www.subnetonline.com/) provides tools
     which allow you to check if specific TCP ports are open for both
-    [IPv4](http://www.subnetonline.com/pages/network-tools/online-port-scanner.php)
-    and [IPv6](http://www.subnetonline.com/pages/ipv6-network-tools/online-ipv6-port-scanner.php) amongst other things.
-
-Other testers on the net:
-
--   [Smurf Amplifier Registry (SAR)](http://www.powertech.no/smurf/) The
-    SAR is a tool for Internet administrators being attacked by or
-    implicated in smurf attacks, or those who wish to take precautions.
+    [IPv4](https://www.subnetonline.com/pages/network-tools/online-port-scanner.php)
+    and [IPv6](https://www.subnetonline.com/pages/ipv6-network-tools/online-ipv6-port-scanner.php)
+    amongst other things.