diff --git a/check_dns.sh b/check_dns.sh
index 848c543..fcf2fa6 100755
--- a/check_dns.sh
+++ b/check_dns.sh
@@ -27,7 +27,7 @@ if [[ -z $query_domain && ${query_domain+x} ]]; then
 fi
 
 # Perform DNS resolution check and measure the time
-start_time=$(date +%s%N)
+start_time=$(date +%s)
 
 if [[ -z "$dns_server" ]]; then
   # The DNS server was not provided.
@@ -37,8 +37,8 @@ else
   result=$(dig @$dns_server "$query_domain" +short)
 fi
 
-end_time=$(date +%s%N)
-response_time=$(((end_time - start_time) / 1000000))
+end_time=$(date +%s)
+response_time=$((end_time - start_time))
 perfdata="response_time=${response_time}ms;${warning_time};${critical_time};0;"
 
 # Check response time against warning and critical levels
diff --git a/packages.txt b/packages.txt
index ede148e..4ec3f62 100644
--- a/packages.txt
+++ b/packages.txt
@@ -6,4 +6,4 @@ smartmontools
 curl
 recode
 python3-pip
-dig
+dnsutils