Update debi.sh

debi.sh

@@ -578,7 +578,7 @@ EOF
     echo "d-i netcfg/get_ipaddress string $ip" | $save_preseed
     [ -n "$netmask" ] && echo "d-i netcfg/get_netmask string $netmask" | $save_preseed
     [ -n "$gateway" ] && echo "d-i netcfg/get_gateway string $gateway" | $save_preseed
-    [ -z "${ip%%*:*}" ] && [ -n "${dns%%*:*}" ] && dns='2001:4860:4860::8888 2001:4860:4860::8844'
+    [ -z "${ip%%*:*}" ] && [ -n "${dns%%*:*}" ] && dns="$dns6"
     [ -n "$dns" ] && echo "d-i netcfg/get_nameservers string $dns" | $save_preseed
     echo 'd-i netcfg/confirm_static boolean true' | $save_preseed
 }