diff --git a/testcases/cli-test/unbound/oe_test_service_unbound-keygen.sh b/testcases/cli-test/unbound/oe_test_service_unbound-keygen.sh
index 7d846b4dfbd36c4f52f15ec87b71729c3205d662..31235969d340ff73e21b0403f0705b468d5e2f59 100644
--- a/testcases/cli-test/unbound/oe_test_service_unbound-keygen.sh
+++ b/testcases/cli-test/unbound/oe_test_service_unbound-keygen.sh
@@ -17,10 +17,12 @@
 # @Desc      :   Test unbound-keygen.service restart
 # #############################################
 
-source "../common/common_lib.sh"
+source "$OET_PATH/testcases/cli-test/common/common_lib.sh"
 
 function pre_test() {
     LOG_INFO "Start environmental preparation."
+    [ -f /etc/resolv.conf-bak ] || cp /etc/resolv.conf /etc/resolv.conf-bak
+    echo "nameserver 127.0.0.1" > /etc/resolv.conf
     DNF_INSTALL unbound
     service=unbound-keygen.service
     log_time=$(date '+%Y-%m-%d %T')
@@ -55,7 +57,8 @@ function run_test() {
 function post_test() {
     LOG_INFO "start environment cleanup."
     systemctl stop "${service}"
-    DNF_REMOVE
+    DNF_REMOVE 1 unbound
+    [ -f /etc/resolv.conf-bak ] && \cp /etc/resolv.conf-bak /etc/resolv.conf 
     LOG_INFO "Finish environment cleanup!"
 }