diff --git a/ci/before_script.sh b/ci/before_script.sh
index a0e87adb9e..1759dbe942 100755
--- a/ci/before_script.sh
+++ b/ci/before_script.sh
@@ -10,6 +10,12 @@ fi
 CI_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "${CI_DIR}/common/build.sh"
 
+# Enable ipv6 on Travis. ref: a39c8b7ce30d
+if ! test "${TRAVIS_OS_NAME}" = osx ; then
+  echo "before_script.sh: enable ipv6"
+  sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=0
+fi
+
 # Test some of the configuration variables.
 if [[ -n "${GCOV}" ]] && [[ ! $(type -P "${GCOV}") ]]; then
   echo "\$GCOV: '${GCOV}' is not executable."
diff --git a/ci/common/build.sh b/ci/common/build.sh
index 02e1110a15..0024f2cbd5 100644
--- a/ci/common/build.sh
+++ b/ci/common/build.sh
@@ -86,12 +86,3 @@ build_nvim() {
 
   cd "${TRAVIS_BUILD_DIR}"
 }
-
-macos_rvm_dance() {
-  # neovim-ruby gem requires a ruby newer than the macOS default.
-  source ~/.rvm/scripts/rvm
-  rvm get stable --auto-dotfiles
-  rvm reload
-  rvm use 2.2.5
-  rvm use
-}