From 3ddb943dc4ed011eedb59902b1457ecf81221027 Mon Sep 17 00:00:00 2001
From: Sergio Correia <scorreia@redhat.com>
Date: Tue, 10 Aug 2021 08:19:16 -0300
Subject: [PATCH] nbde-introduction: include steps to open the tang port in the
 firewall

So that we can access it from other machines.
---
 nbde-introduction/background.sh |  6 ++++++
 nbde-introduction/step2.md      | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/nbde-introduction/background.sh b/nbde-introduction/background.sh
index 9f935f0e..0af955f5 100755
--- a/nbde-introduction/background.sh
+++ b/nbde-introduction/background.sh
@@ -27,6 +27,11 @@ setup_swap() {
     log "swap file set up successfully..."
 }
 
+set_default_firewall_zone() {
+    firewall-cmd --set-default-zone libvirt
+    log "Default firewall zone set to libvirt"
+}
+
 ubuntu_deps() {
     log "(OS=ubuntu) Installing additional packages..."
 
@@ -44,6 +49,7 @@ rhel8_deps() {
     dnf -y module install virt
     systemctl start libvirtd
     log "Packages installed successfully..."
+    set_default_firewall_zone
 }
 
 install_deps() {
diff --git a/nbde-introduction/step2.md b/nbde-introduction/step2.md
index 0b83d05f..29727745 100644
--- a/nbde-introduction/step2.md
+++ b/nbde-introduction/step2.md
@@ -34,3 +34,24 @@ This indicates that the server is responding as expected.
 
 Note that the actual values for the `payload` and other fields in the JSON will differ from
 the example output displayed above.
+
+## Opening the port used by `tang` in the firewall
+
+Finally, we should make sure we can access `tang` from other machines, which means the port it is listening to should
+be reachable from these other machines. By default, `tang` works on TCP port 80 -- the same as the HTTP protocol --, so
+we can open it in our scenario by issuing the following command:
+
+`firewall-cmd --add-port=80/tcp`{{execute}}
+
+Note: depending on how the firewall is set up, the command to open a specific port may be slightly different, but for our
+scenario the command above will suffice.
+
+You can verify the port is open by issuing the next command:
+
+`firewall-cmd --list-ports`{{execute}}
+
+And the expected output here would be the following:
+
+```
+80/tcp
+```