How do ptr work

In his spare time he likes to paint model airplanes. Another post in our Quick Tips series, offering helpful tips for getting the most out of your Intermedia services. This edition talks about the mystery of missing message bodies in Outlook […].

We're happy to help you stay connected Learn more. Toggle navigation. Phillip Lewis February 12, Tags: admins , IT , system administration. For this, both the IPv4 and IPv6 addresses are valid.

But there is one special characteristic to keep in mind: reverse mapping is used here. The IP address is therefore specified in reverse sequence. If using an IPv4 address, however, it only involves octets.

Within the specific groups, the serial number sequence remains unchanged. Even leading zeros , which are normally omitted in hexadecimal notation, are written out in PTR records.

The zone also has to be specified. Here, there are two that are possible, again depending on whether an IPv4 or IPv6 address is concerned. The former receives the extension in-addr. This means that the domain names both in the name field and in the resource data always end with a period. This separates the top-level domain TLD from the root directory, which is nevertheless represented as an empty field.

The time to live specifies the duration that a record is still valid for. If the time period has lapsed, the information has to be requested again. This way, the DNS avoids the problem of having possibly outdated records held in the cache, which can then lead to connection issues. Usually, however, this field does not appear in the record itself.

The TTL is specified in seconds. Today, the class field is only of historical significance. Both are no longer used, which is why only internet is possible for the class. For this reason, this field normally contains the abbreviation IN or is completely omitted. When left blank, the system is based on the usual standard, which in turn is the internet. For this kind of record, the type is understandably always PTR.

In the final data field, the domain name can then be found — again in FQDN notation. The address reads c and The opinions expressed in this blog are those of the author and do not necessarily represent those of ITworld, its parent, subsidiary or affiliated companies.

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