diff --git a/bin/tests/system/ifconfig.sh.in b/bin/tests/system/ifconfig.sh.in
index 60dbf8b9e6..7930d67d02 100755
--- a/bin/tests/system/ifconfig.sh.in
+++ b/bin/tests/system/ifconfig.sh.in
@@ -82,11 +82,11 @@ up() {
       ;;
     *-*-linux*)
       if [ "$use_ip" ]; then
-        ip address add $a/24 dev lo:$int
-        ip link set dev lo:$int mtu 1500
+        [ "$a" ] && ip address add $a/24 dev lo:$int
+        [ "$a" ] && ip link set dev lo:$int mtu 1500
         [ "$aaaa" ] && ip address add $aaaa/64 dev lo
       else
-        ifconfig lo:$int $a up netmask 255.255.255.0 mtu 1500
+        [ "$a" ] && ifconfig lo:$int $a up netmask 255.255.255.0 mtu 1500
         [ "$aaaa" ] && ifconfig lo inet6 add $aaaa/64
       fi
       ;;