diff --git a/books/beaglebone-cookbook/05tips/tips.rst b/books/beaglebone-cookbook/05tips/tips.rst
index b867ebdc39375af364a61fdd271afafd529338e3..24b4d868dc407ea52e9868dd2e5fc02503134f2a 100644
--- a/books/beaglebone-cookbook/05tips/tips.rst
+++ b/books/beaglebone-cookbook/05tips/tips.rst
@@ -940,21 +940,21 @@ Web servers typically listen to port *80*. First, look up the IP address of your
.. code-block:: bash
- host$ ifconfig
- eth0 Link encap:Ethernet HWaddr 00:e0:4e:00:22:51
- inet addr:137.112.41.35 Bcast:137.112.41.255 Mask:255.255.255.0
- inet6 addr: fe80::2e0:4eff:fe00:2251/64 Scope:Link
- UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
- RX packets:5371019 errors:0 dropped:0 overruns:0 frame:0
- TX packets:4720856 errors:0 dropped:0 overruns:0 carrier:0
- collisions:0 txqueuelen:1000
- RX bytes:1667916614 (1.6 GB) TX bytes:597909671 (597.9 MB)
-
- eth1 Link encap:Ethernet HWaddr 00:1d:60:40:58:e6
- ...
-
-
-It's the number following *inet addr:*, which in my case is *137.112.41.35*.
+ host$ ip a
+ 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
+ link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
+ inet 127.0.0.1/8 scope host lo
+ valid_lft forever preferred_lft forever
+ inet6 ::1/128 scope host
+ valid_lft forever preferred_lft forever
+ 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1280 qdisc mq state UP group default qlen 1000
+ link/ether 00:15:5d:7c:e8:dc brd ff:ff:ff:ff:ff:ff
+ inet 172.31.43.210/20 brd 172.31.47.255 scope global eth0
+ valid_lft forever preferred_lft forever
+ inet6 fe80::215:5dff:fe7c:e8dc/64 scope link
+ valid_lft forever preferred_lft forever
+
+It's the number following *inet*, which in my case is *172.31.43.210*.
.. tip::
@@ -968,7 +968,7 @@ Then run the following, using your host's IP address:
.. code-block:: bash
host$ sudo iptables -t nat -A PREROUTING -p tcp -s 0/0 \
- -d 137.112.41.35 --dport 1080 -j DNAT --to 192.168.7.2:80
+ -d 172.31.43.210 --dport 1080 -j DNAT --to 192.168.7.2:80
Now browse to your host computer at port *1080*. That is, if your host's IP address
@@ -997,11 +997,11 @@ First install and check the status:
.. code-block:: bash
+ bone$ sudo apt update
bone$ sudo apt install ufw
bone$ sudo ufw status
Status: inactive
-
Now turn off everything coming in and leave on all outgoing.
Note, this won't take effect until *ufw* is enabled.
@@ -1034,9 +1034,10 @@ Just to be sure, you can install *nmap* on your host computer to see what ports
80/tcp open http
3000/tcp open ppp
-Nmap done: 1 IP address (1 host up) scanned in 0.19 seconds
+ Nmap done: 1 IP address (1 host up) scanned in 0.19 seconds
-Currently there are three ports visible: 22, 80 and 3000 (visual studio code) Now turn on the firewall and see what happens.
+Currently there are three ports visible: 22, 80 and 3000 (visual studio code).
+Now turn on the firewall and see what happens.
.. code-block:: bash
@@ -1053,8 +1054,7 @@ Currently there are three ports visible: 22, 80 and 3000 (visual studio code) N
PORT STATE SERVICE
22/tcp open ssh
-Nmap done: 1 IP address (1 host up) scanned in 0.19 seconds
-
+ Nmap done: 1 IP address (1 host up) scanned in 0.19 seconds
Only port 22 (ssh) is accessible now.
@@ -1066,7 +1066,7 @@ The firewall will remain on, even after a reboot. Disable it now if you don't wa
Firewall stopped and disabled on system startup
-See the How-To Geek article for more examples.
+See the `How-To Geek article <https://www.howtogeek.com/devops/how-to-secure-your-linux-server-with-a-ufw-firewall/>`_ for more examples.
.. _tips_apt: