Workaround for Arduino mDNS output noise.

See https://forum.arduino.cc/index.php?topic=469428.0
See per1234/arduino-ci-script#1
Arduino IDE adds a lot of noise caused by network traffic (mDNS?),
because it's listening for network-attached devices. Attempt to
firewall it in the TravisCI environment to prevent polluted error logs....

Author: henrygab

.travis.yml

@@ -1,3 +1,4 @@
+sudo: required
 language: c
 dist: xenial
 git:
@@ -52,6 +53,17 @@ install:
   - rm -r $BSP_PATH/*
   - ln -s $TRAVIS_BUILD_DIR $BSP_PATH/$BSP_VERSION
   - arduino --install-library "Adafruit NeoPixel","Adafruit NeoMatrix","Adafruit GFX Library","Adafruit SSD1306","MIDI Library","Adafruit ILI9341","Adafruit HX8357 Library"
+  # TODO: find way to filter out the noisy mDNS output from arduino IDE...
+  # See https://forum.arduino.cc/index.php?topic=469428.0
+  # See https://github.com/per1234/arduino-ci-script/issues/1
+  # Arduino IDE adds a lot of noise caused by network traffic (mDNS?)
+  # The following lines attempt to firewall it to prevent polluted error logs....
+  - sudo iptables -P INPUT DROP
+  - sudo iptables -P FORWARD DROP
+  - sudo iptables -P OUTPUT ACCEPT
+  - sudo iptables -A INPUT -i lo -j ACCEPT
+  - sudo iptables -A OUTPUT -o lo -j ACCEPT
+  - sudo iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
 
 before_script: