diff --git a/.gitignore b/.gitignore
index 4c3333a..331a669 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,4 @@ pubkey
 .ses_secret
 ansible/credentials
 terraform/dns_*.tf
+config.mk.bak
diff --git a/configure b/configure
index cf5fb11..c8e88d4 100755
--- a/configure
+++ b/configure
@@ -67,7 +67,12 @@ while read LINE <&4; do
 done 4< <(cat config.mk.in)
 
 echo
-echo "All done!  Putting your configuration into config.mk"
 
+if [[ -e config.mk ]]; then
+    echo "Backing up your old config to config.mk.bak"
+    cp config.mk config.mk.bak
+fi
+
+echo "All done!  Putting your configuration into config.mk."
 mv $TEMPFILE config.mk