diff --git a/config/config.go b/config/config.go
index bb67000b..02c691c0 100644
--- a/config/config.go
+++ b/config/config.go
@@ -817,7 +817,11 @@ func parseDNS(rawCfg *RawConfig, hosts *trie.DomainTrie[netip.Addr], rules []C.R
 		host, _, err := net.SplitHostPort(ns.Addr)
 		if err != nil || net.ParseIP(host) == nil {
 			u, err := url.Parse(ns.Addr)
-			if err != nil || net.ParseIP(u.Host) == nil {
+			if err == nil {
+				if ip, _, err := net.SplitHostPort(u.Host); err != nil || net.ParseIP(ip) == nil {
+					return nil, errors.New("default nameserver should be pure IP")
+				}
+			} else {
 				return nil, errors.New("default nameserver should be pure IP")
 			}
 		}