This article confirms whether UltraDNS supports Extension Mechanisms for DNS (EDNS0).
It applies when reviewing DNS compatibility, troubleshooting advanced DNS behavior, or validating resolver functionality.
Support for EDNS0
Yes, UltraDNS currently supports EDNS0.
What This Means
EDNS0 extends DNS protocol functionality beyond its original limitations. It enables features such as larger UDP packet sizes and additional DNS options.
UltraDNS authoritative name servers support EDNS0 as part of standard DNS operations.
Verification
On macOS or Linux (using dig):
dig example.com +edns=0
In the response, look for an OPT PSEUDOSECTION indicating EDNS is present.
On Windows (using nslookup):
nslookup -type=txt example.com
While nslookup does not explicitly display EDNS flags, you can confirm proper DNS resolution. For detailed EDNS validation on Windows, install BIND tools and use:
dig example.com +edns=0
If the response includes EDNS-related output without errors, EDNS0 is supported.