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Compare the SOA serial on all nameservers

harmlessDNSdebian, ubuntu
Adjust the values, the command updates live
user@server
for ns in $(dig +short example.com NS); do echo "$ns $(dig +short @$ns example.com SOA | awk '{print $3}')"; done

Finds all nameservers of the domain and prints the serial number from the SOA record for each one. Different numbers show that a secondary has not yet picked up the latest zone change. Resolvers then return old or new answers depending on which nameserver they ask.

Also searched as

  • secondary nameserver out of sync
  • check if zone updated on slave
  • nameservers return different answers

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Check the CAA record of a domain

$dig +short example.com CAA
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Check whether DNSSEC works for a domain

$dig @1.1.1.1 +dnssec example.com SOA | grep -E "flags:|RRSIG|status:"
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