SOA Serial Number Format is Invalid and SOA Expire Value out of recommended range?


A famous Email health reporting returns for my domain hosted at Cloudflare :

  • SOA Serial Number Format is Invalid
    The serial number is an unsigned 32 bit value assigned to your SOA record must be between 1 and 4294967295.
    We will issue a warning if your serial is either invalid by being outside of the allowed range or if it does not conform to this format.

In fact, for my domain, SOA Serial number is 2279385176 so it seems to be OK. Strange…

  • SOA Expire Value out of recommended range
    A name server will no longer consider itself Authoritative if it hasn’t been able to refresh the zone data in the time limit declared in this value.

Additional Information :
Each DNS host has their own interface, but you are looking for either a setting labeled Expire Value or you might have to enter your SOA details manually. If you have to enter your SOA then the Expire value will be second to last number in the SOA.

Your DNS records are hosted on two or more DNS servers that are supposed to be in regular contact with each other so that they have up to date copies of your DNSrecords. The Expire Value setting tells each slave server how long it is allowed to continue giving out authoritative replies after it has no longer heard from the master server.

RFC 1912 recommends 1209600 - 2419200 seconds (14-28 days).

In fact, for my domain, SOA Expire value is 7 days.

Is it possible to modify those values in order to respect RFC recommendations ?

Thanks in advance for your help.


They’re just recommendations / warnings really - no issues are going to crop up just because it doesn’t follow them.

As far as if you can change them yourself, no. They’re managed by Cloudflare directly.

Maybe those recommendations are valid for a smaller provider, but the scale of Cloudflare makes it near impossible that both of your nameservers will be knocked off for long enough for the SOA expiry to matter.

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