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Resolution Record Type Constraints

Last Updated: May 27, 2016
  • The DNS API supports the following resolution types: Supported resolution record types: A, CNAME, NS, MX, TXT, SRV, AAAA, and URL forwarding (implicit and explicit).
  • All RR values may only contain letters, numbers, "-", ".", "*", "@", and "Chinese characters". Some records may be blank, i.e. the "@" symbol. The letters are not case sensitive. "-" cannot be placed at the beginning or end. "." is used as a separator and two periods cannot be placed successively. "." separates strings of up to 63 characters. The total length of the RR value (including ".") cannot exceed 253 characters.
  • The IP address is a legal IP address. Private IP addresses are also allowed. IPv4 is expressed in dotted decimal format, where "." is used to separate 4 sets of numbers, with each set no greater than 255 and not beginning with 0. For example, is a legal IPv4 address, but is not.
  • IPv6 uses 16 digits as a group and ":" to separate the value into 8 groups of 4 hexadecimal digits.
    For example, xxxx: xxxx: xxxx: xxxx: xxxx: xxxx: xxxx: xxxx. Here, x has the possible values including 0-9, a, b, c, d, e, and f (case-insensitive).
    In addition, IPv6 addresses can be written in a simplified format where groups of consecutive 0s are omitted and replaced with "::", regardless of how many groups are omitted in this way. For example, 2001:DB8:2de:0:0:0:0:e13 can be simplified as 2001:DB8:2de::e13.
  • URL forwarding does not support pan resolution, only the default line.
  • The target domain name for URL forwarding cannot be a Chinese domain name.
  • As required by the Ministry of Industry's policy concerning domain jump services, the URL forwarding function currently only supports websites with an ICP license number and that use HiChina as their access service provider. Other websites are not supported at the moment.