Expand your access to more types of DNS records! Our DNS product line delivers comprehensive and accurate DNS data, empowering you with intelligence that helps fortify networks, add context to threat indicators, and expand asset discovery.
Gain access to historical DNS data with industry-leading coverage of unique fully qualified domain names (FQDNs) across diverse DNS record types.
Explore DatabaseRetrieve essential DNS data, such as IP addresses and MX and NS records for any domain with a developer-friendly API.
Explore APIGet instant insights into a domain's DNS configuration, including its IP address and MX, NS, and TXT records with our web tool.
Explore LookupAutomate forward (FQDN to IP) and reverse (IP to FQDN) DNS history searches via our robust API.
Explore APIConduct quick historical domain IP lookups (forward) or reverse IP searches to find associated domains using our intuitive GUI.
Explore Lookup"我们希望为所有 Cyberscape 用户提供整合网络威胁调查相关数据的能力。WhoisXML API 所提供的独特数据将对网络威胁调查社区有所帮助，分析师可以缩短了解和缓解威胁的周期"。
"WhoisXML 改变了我们的游戏规则，可快速识别所有那些为网络犯罪分子提供物质支持的供应商，这些犯罪分子使用看似合法实则使用非常复杂的网站，从而彻底颠覆了我们在过程中侦破网络犯罪的能力。通过快速识别这些在不知情的情况下位犯罪分子提供支持的供应商，可协助其以公共利益为目的，摧毁犯罪分子的基础设施。”
A canonical name (CNAME) record is a DNS record type that designates a domain or subdomain as an alias for another domain. Unlike A or AAAA records, a CNAME points to a domain or subdomain, not an IP address. When a DNS query is made for a domain with a CNAME, the DNS server performs an additional lookup to resolve the canonical domain's IP address.
When a client (like your web browser) wants to access a web address like www.example.com that has a CNAME record, the DNS resolver contacts the authoritative name server (NS) for example.com. Since the domain has a CNAME record, the authoritative NS responds with the CNAME (e.g., example1.com), rather than an IP address.
The DNS resolver performs another query, this time for example1.com. If this query resolves to an A or AAAA record, the resolver can provide the client with the IP address it needs to load the website.
CNAME records are particularly useful when integrating your domain with a content delivery network (CDN) or other third-party services. You can use a CNAME that points to their service domain. This allows you to maintain control over your domain name while the CDN provider manages its server's DNS settings, even if their IP addresses change. This ensures continuous service without requiring you to update your DNS records constantly.
You may also need to use CNAME records when your domain has different country-code top-level domains (ccTLDs), such as example.us, example.es, and example.fr, so you can redirect these domains to the parent domain (example.com).
CNAME record lookups help identify dangling CNAMEs (i.e., decommissioned services with CNAMEs that remain active) that pave the way for subdomain takeovers and potentially lead to phishing and malware. Analyzing CNAME chains can reveal hidden malicious infrastructures, enabling threat investigators to map malicious networks.
CNAME records have some limitations. For one, a domain or subdomain can only have one CNAME record, and this must always point to another domain name, not an IP address. CNAME records cannot coexist with any other record type (like an A, MX, or NS record) for the same domain (DNSSEC records are an exception to this rule). Consequently, root domains cannot use CNAMEs as they require essential start of authority (SOA) and NS records. Additionally, MX and NS records must not point to a domain that has a CNAME record.
These restrictions are detailed in certain sections 10.1 and 10.3 of RFC 2181 and section 3.6 of RFC 1034.
You may use our DNS Lookup API, which returns CNAME and other DNS record types or our lookup tool. If you only want to look up the TXT record of a domain, you can use our free TXT Lookup tool.
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