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GEO - Additional Record Types Supported

This article relates to LoadMaster firmware version 7.2.53.

In LoadMaster firmware version 7.2.53, GEO Global Server Load Balancing (GSLB) has been enhanced to support additional record types for domains, as follows:

  • Multiple TXT and CNAME records per Fully Qualified Domain Name (FQDN).

  • One MX record per FQDN.

These record types allow you to communicate domain resources to clients:

  • A TXT (text) record is essentially unformatted data that can be used for almost any purpose, but typically contains information to be consumed by clients to classify a domain in some way, provide details about a domain, or specify resources available within a domain.

  • A CNAME record points a DNS name (such as www.example.com) to another DNS name (such as lb.example.com). This is typically used to define a website alias.

  • A mail exchanger (MX) record specifies the mail server responsible for accepting email messages on behalf of a domain name.

To configure records for a specific FQDN, in the LoadMaster User Interface (UI), go to Global Balancing > Manage FQDNs and click Modify on the relevant FQDN. A new Additional Records section has been added. You can add, modify, or delete a TXT, CNAME, or MX record in this section.

The following limits are in place:

  • There is a limit of 127 characters in the Data field.

  • There is a limit of 64 records of any type per FQDN.

  • There is a global maximum of 1024 resource records.

The following validation is in place for CNAME records:

  • There cannot be duplicates.

  • CNAMEs you add must be part of the domain (must be a child of the FQDN and not the same as the FQDN).

  • CNAMEs must be a domain name (no IP addresses).

  • FQDNs cannot be added if it already exists as a CNAME.

  • Zones cannot be added if it already exists as a CNAME.

  • A CNAME cannot be added if an FQDN with the same name already exists.

  • A CNAME cannot be added if a Zone with the same name already exists.

The Time To Live (TTL) value is taken from either the global setting (in Global Balancing > Miscellaneous Params) or the local setting in the FQDN (if the Enable Local Settings check box is selected).

For the MX record, there is also a priority. Valid values for the priority field range from 0 to 65535.

The following are not supported as of firmware version 7.2.53:

  • Multiple strings within the record: Some DNS providers allow you to put multiple strings in one entry using quotes, for example, "string 1" "string 2" "string 3". Kemp does not allow this as of firmware version 7.2.53, so you can only have "string 1", for example.
  • Non-ASCII characters
  • Backslashes (\)

Duplicate records are allowed.

You can also configure a global TXT record. For further details, refer to the following article: GEO TXT Record Support. Records are returned with requests to the specific domain.

RESTful Application Programming Interface (API) Details

You can retrieve the existing TXT, CNAME, and MX records for an FQDN by running the showfqdn command. For example:

/access/showfqdn?fqdn=<FQDNName>

The Index number for each record is shown in the output - this can be used to modify or delete an existing record.

You can add a new TXT record to an FQDN by running the addrr command. For example:

/access/addrr?fqdn=<FQDNName>&type=txt&rdata=<ResourceRecordData>

You can add a new CNAME record to an FQDN by running the addrr command. For example:

/access/addrr?fqdn=<FQDNName>&type=cname&name=<Name>

You can add a new MX record to an FQDN by running the addrr command. For example:

/access/addrr?fqdn=<FQDNName>&type=mx&rdata=<ResourceRecordData>

You can modify an existing TXT record by running the modrr command. For example:

/access/modrr?fqdn=<FQDNName>&type=txt&param=rdata&value=<UpdatedResourceRecordData>&id=<IndexOfRecord>

You can modify an existing CNAME record by running the modrr command. For example:

/access/modrr?fqdn=<FQDNName>&type=cname&param=name&value=<UpdatedName>&id=<IndexOfRecord>

You can modify an existing MX record by running the modrr command. For example:

/access/modrr?fqdn=Example.com&type=mx&id=<IndexOfRecord>&param=<rdata/priority>&value=<Value>

When modifying an MX record, you can specify either the rdata or priority as the param, depending on what parameter you want to modify the value for.

You can delete an existing TXT, CNAME, or MX record by running the dellrr command. For example:

/access/delrr?fqdn=<FQDNName>&id=<Index>

To retrieve the Index number of an existing record, run the showfqdn command.

For further details on the RESTful API in general, refer to the Long Term Support (LTS) RESTful API Interface Description document.


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