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101 · Question #116

A site wishes to delegate the name .wmysite.com to a GTM System. Which entry would be appropriate in their current DNS servers?

The correct answer is C. iw.mysite.com. IN CNAME wwip.mysite.com.. To delegate a hostname to an F5 GTM WideIP, the upstream DNS server should use a CNAME record pointing the name to the WideIP name on the GTM.

Section 1: OSI Model, Network, and Application Delivery Basics

Question

A site wishes to delegate the name .wmysite.com to a GTM System. Which entry would be appropriate in their current DNS servers?

Options

  • Avww.mysite.com. IN A 132.26.33.15
  • B15.33.addrin.arpa.com IN PRT .wiw.mysite.com.
  • Ciw.mysite.com. IN CNAME wwip.mysite.com.
  • Dwwmysite.com. IN DEL wiwGTM.mysite.com.

How the community answered

(22 responses)
  • A
    9% (2)
  • B
    5% (1)
  • C
    82% (18)
  • D
    5% (1)

Why each option

To delegate a hostname to an F5 GTM WideIP, the upstream DNS server should use a CNAME record pointing the name to the WideIP name on the GTM.

Avww.mysite.com. IN A 132.26.33.15

An A record maps a hostname directly to a static IP address and does not delegate resolution authority to the GTM System.

B15.33.addrin.arpa.com IN PRT .wiw.mysite.com.

A PTR record is used for reverse DNS lookups mapping an IP address back to a hostname, which is not applicable for forward name delegation.

Ciw.mysite.com. IN CNAME wwip.mysite.com.Correct

A CNAME record redirects resolution of the alias name to the canonical WideIP name managed by the GTM System. When a client queries the aliased name, the upstream DNS returns the CNAME pointing to the GTM WideIP, and the GTM then applies its load-balancing and health-check logic to return the appropriate IP address.

Dwwmysite.com. IN DEL wiwGTM.mysite.com.

DEL is not a valid DNS record type - no such record type exists in the DNS standard, making this option syntactically invalid.

Concept tested: F5 GTM WideIP CNAME delegation from upstream DNS

Source: https://techdocs.f5.com/en-us/bigip-15-1-0/big-ip-gtm-implementations.html

Topics

#DNS delegation#CNAME record#GTM#DNS zone records

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