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  • About CNAME Lookup - Online CNAME Checker

    CNAME Lookup lets you find the CNAME record for any domain or subdomain. The online tool allows you to query the DNS servers and shows whether or not the canonical name is configured for the given domain or subdomain.

    What is a DNS CNAME record?

    A CNAME record, also known as canonical name or alias record, is a DNS record type used in place of A (for IPv4) or AAAA (for IPv6) record when the domain or subdomain is an alias of another domain.

    All CNAME records must point to a domain name, not an IP address. Suppose, for example, the subdomain www, which is an alias of the root domain abc.com. The users accessing www.abc.com are referred to a root domain (or DNS zone apex). That means a DNS query that hits the DNS server for DNS records of www.abc.com triggers another DNS lookup query, for abc.com, to get an IP address via its A or AAAA record.

    What is a CNAME example?

    An example of a CNAME record is

    Record Type Value TTL
    www CNAME abc.com 3600

    www CNAME abc.com 3600

    In the above example,

    • www is the subdomain and is an identifier of the record.
    • CNAME is the DNS record type.
    • abc.com is the value of the record. That means www will resolve to the IP address of the domain abc.com.
    • 3600 is TTL (time to live) is the expiry time of the CNAME record. It's expressed in seconds. Here 3600 means that the records will be updated after each hour.

    What are the common uses of CNAME records?

    Some common uses of CNAME records are

    • You only need to configure the IP address once. For example, the domain abc.com points to A or AAAA records, and the CNAME record for subdomain www points to the main domain. While updating the IP address, you only need to update the A or AAAA record of the main domain. The record for the subdomain will be automatically updated.
    • Providing a separate hostname for third-party services, like email or FTP, points it to the main domain. Suppose you want to configure the domain name for a third-party service. In that case, you control your domain name, but the third-party service manages the servers that host it. Therefore, it would be inconvenient to change your DNS settings whenever the third-party service changes its DNS settings. Consequently, it would be requested to create a CNAME record instead. In that case, you have control over your domain name, and the third-party service can change the DNS configuration of their service at any time when needed.
    • Many hosted services offer a particular subdomain to each customer on the service provider's domain (abc.hostname.com) and use the CNAME to point it to the customer's domain (www.abc.com).
    • Facilitates registering the same domain in different country versions and pointing them to the main ".com" domain.
    • Points the several websites owned by the same organization to their main domain.
    • Often the TXT records are used for domain verification. But sometimes, the provider may generate the unique verification code as a subdomain and ask to point it to prove the ownership of the main domain.

    How to perform the DNS Lookup to check the CNAME records?

    There are two ways to perform the CNAME Lookup, either through manual checking or online tools.

    Manual checking of the CNAME records

    You can divide it into two parts

    1. CNAME Lookup on Windows-based systems

      Windows-based systems, including Windows 7, Windows 10 & Windows Server, use the nslookup command to perform the CNAME Lookup either using your local resolver or specify any public recursive resolver.

      1. For locally configured resolver nslookup
        > set q=cname
        > www.abc.com
      2. For any specific public recursive resolver nslookup
        > set q=cname
        > server 8.8.8.8
        > www.abc.com
    2. CNAME Lookup on Linux and Mac systems

      On Linux and Mac-based systems, including Mac OS X, MacOS, Ubuntu, Debian, CentOS & Red Hat, you can use the host command or dig command to perform the CNAME Lookup either using your local resolver or specify any public recursive resolver.

      Using the host command

      1. For locally configured resolver host -t cname www.abc.com
      2. For any specific public recursive resolver host -t cname www.example.com 8.8.8.8

      Using the dig command

      1. For locally configured resolver dig www.abc.com cname
      2. For any specific public recursive resolver dig @8.8.8.8 www.abc.com cname

    Checking of the CNAME records using an online tool

    To check the CNAME records of a domain, perform the following steps.

    Some restrictions on CNAME records

    • The CNAME record cannot be placed at the root domain level. Because the root domain level is the DNS Start of Authority (SOA), that must point to an IP address.
    • The CNAME must point to another valid domain or subdomain, not an IP address.
    • The hostname defined in the CNAME record must not have other records present except for DNSSEC records (RRSIG, DNSKEY, DS, NSEC, and NSEC3PARAM).
    • The MX or NS record cannot point to the CNAME alias.
    • The CNAME record can point to another CNAME record, but it involves several DNS Lookup queries. That's technically not recommended because it slows down the user experience.
    • The CNAME records do not always resolve to the same website as the domain it points to. The CNAME record only points to the IP of the root domain.
    • You can set at most one CNAME record for a domain or subdomain.