diff --git a/0x11-what_happens_when_your_type_google_com_in_your_browser_and_press_enter/2-contribution-to_what-happens-when_github_answer b/0x11-what_happens_when_your_type_google_com_in_your_browser_and_press_enter/2-contribution-to_what-happens-when_github_answer
new file mode 100644
index 0000000..0e7dabb
--- /dev/null
+++ b/0x11-what_happens_when_your_type_google_com_in_your_browser_and_press_enter/2-contribution-to_what-happens-when_github_answer
@@ -0,0 +1 @@
+https://github.com/StevOti/alx-system_engineering-devops/pull/1#issue-2242483601
diff --git a/0x11-what_happens_when_your_type_google_com_in_your_browser_and_press_enter/what-happens-when b/0x11-what_happens_when_your_type_google_com_in_your_browser_and_press_enter/what-happens-when
new file mode 160000
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--- /dev/null
+++ b/0x11-what_happens_when_your_type_google_com_in_your_browser_and_press_enter/what-happens-when
@@ -0,0 +1 @@
+Subproject commit ff2e421a0864994e5f0b4e79e3655602cb95f442
diff --git a/0x13-firewall/0-block_all_incoming_traffic_but b/0x13-firewall/0-block_all_incoming_traffic_but
new file mode 100755
index 0000000..63896f9
--- /dev/null
+++ b/0x13-firewall/0-block_all_incoming_traffic_but
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Configure a ufw firewall to block all incoming traffic
+# except for TCP ports 22, 80 and 443
+
+sudo apt install ufw
+sudo ufw default deny incoming
+sudo ufw default allow outgoing
+sudo ufw allow 22/tcp
+sudo ufw allow 443/tcp
+sudo ufw allow 80/tcp
+sudo ufw enable
+sudo ufw status verbose
diff --git a/0x13-firewall/README.md b/0x13-firewall/README.md
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--- /dev/null
+++ b/0x13-firewall/README.md
@@ -0,0 +1 @@
+0x13. Firewall