Home / server / Questions / 803033
Accepted
Vingtoft
Asked: 2016-09-15 07:34:06 +0800 CST

Should I append a dot (.) at the end of my DNS urls?

  • 772

Ive noticed that AWS's DNS service (Route53) appends a dot (.) at the end of every DNS url:

ns-xxx.awsdns-yy.co.uk.
ns-xxx.awsdns-yy.net.
ns-xxx.awsdns-yy.org.
ns-xxx.awsdns-yy.com.

Question: Is this a bug, or should I include the . in my DNS settings?

domain-name-system amazon-web-services amazon-route53

1 Answers

  1. Best Answer

    The dot at the end is correct.

    It's a little-known fact, but fully-qualified (unambiguous) DNS domain names have a dot at the end. People running DNS servers usually know this (if you miss the trailing dots out, your DNS configuration is unlikely to work) but the general public usually doesn't. A domain name that doesn't have a dot at the end is not fully-qualified and is potentially ambiguous. This was documented in the DNS specification, RFC 1034, way back in 1987:

    Since a complete domain name ends with the root label, this leads to a
printed form which ends in a dot.  We use this property to distinguish between:

   - a character string which represents a complete domain name
     (often called "absolute").  For example, "poneria.ISI.EDU."

   - a character string that represents the starting labels of a
     domain name which is incomplete, and should be completed by
     local software using knowledge of the local domain (often
     called "relative").  For example, "poneria" used in the
     ISI.EDU domain.

    From here

    • 40