NSvera port 53 test  2026-10-06T06:56:29+00:00  PHP 8.3.35
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a.root-servers.net IPv4 (198.41.0.4)
  UDP: OK  159 ms, rcode=0, referral NS=5, glue=10
  TCP: OK  317 ms, rcode=0, referral NS=5
k.root-servers.net IPv4 (193.0.14.129)
  UDP: OK  13 ms, rcode=0, referral NS=5, glue=10
  TCP: OK  25 ms, rcode=0, referral NS=5
a.root-servers.net IPv6 (2001:503:ba3e::2:30)
  UDP: FAIL (socket: Network is unreachable)
  TCP: FAIL (connect: Network is unreachable)

Extensions: sockets=yes intl=yes (intl gives IDN/punycode support)
disable_functions: exec,passthru,shell_exec,system

What to look for: IPv4 UDP and TCP must both say OK. IPv6 is nice to have.