XX-net/XX-Net · warning

DNS query:%s not valid, type:%d

Error message

DNS query:%s not valid, type:%d

What it means

The caller asked to resolve a hostname that failed the is_valid_hostname check (bad characters, wrong label length, or empty), so the resolver refuses to query and returns []. This is input validation, not a network failure.

Source

Thrown at code/default/smart_router/local/dns_query.py:673

    def query_unknown_domain(self, domain, dns_type):
        res = self.local_dns_resolve.query(domain, dns_type)
        if res:
            return res

        return self.parallel_query.query(domain, dns_type, [
            self.https_query.query,
            self.tls_query.query,
            self.tcp_query.query,
            query_dns_from_xxnet
        ])

    def query(self, domain, dns_type=1, history=[]):
        domain = utils.to_bytes(domain)
        if utils.check_ip_valid(domain):
            return [domain]

        if not self.is_valid_hostname(domain):
            xlog.warn("DNS query:%s not valid, type:%d", domain, dns_type)
            return []

        ips = g.domain_cache.get_ips(domain, dns_type)
        if ips:
            return ips

        rule = g.user_rules.check_host(domain, 0)
        if rule == "black":
            # user define black list like advertisement or malware server.
            ips = ["127.0.0.1"]
            xlog.debug("DNS query:%s in black", domain)
            return ips

        elif b"." not in domain or g.gfwlist.in_white_list(domain) or rule in ["direct"] or g.config.pac_policy == "all_Direct":
            ips = self.local_dns_resolve.query(domain, timeout=1)
            g.domain_cache.set_ips(domain, ips, dns_type)
            return ips

View on GitHub (pinned to cfa5bc17b6)

Solutions

1. Log/sanitize the domain before querying: strip invalid characters, verify label lengths
2. Fix the upstream code that produced the malformed hostname (e.g. URL parser)
3. Relax is_valid_hostname if underscores must be supported for internal names

Example fix

// before
ips = resolver.query(domain)
// after
if not resolver.is_valid_hostname(domain):
    domain = sanitize(domain)  # strip invalid chars, truncate labels
ips = resolver.query(domain)

def is_queryable(domain):
    return bool(domain) and len(domain) <= 253 and all(
        0 < len(l) <= 63 and all(c.isalnum() or c == '-' for c in l)
        for l in domain.rstrip('.').split('.'))

def is_valid_domain_name(d: bytes) -> bool:
    try:
        name = d.decode('idna') if isinstance(d, bytes) else d
        return is_queryable(name.lower().strip('.'))
    except Exception:
        return False

When it happens

Trigger: Calling BaseResolver.query() (or subclass) with a domain containing invalid characters, labels longer than 63 chars, total length over 253, or a malformed name produced by upstream parsing.

Common situations: Passing a hostname with underscores or wildcards, a trailing artifact like a null byte, or garbage extracted from a URL/SNI field; some browsers/apps generate names with underscores that strict validators reject.

Understand the failure class

• DNS resolution errors: ENOTFOUND and getaddrinfo failures — how hostname lookups fail and how to debug them.

Related errors

• Servers could not be resolved, %r.
• DoH request no name
• query_dns_from_xxnet fail status:%d, cost=%f
• query_dns_from_xxnet %s json:%s parse fail:%s
• remove local DNS server %s from upstream

AI-assisted analysis of XX-net/XX-Net@cfa5bc17b6 (2026-08-27). Data as JSON: /api/errors/8e5cfd4107d67ac5. Report an issue: GitHub.