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SOA values

(2019-09-11)

I've only been doing this for 25 years, I guess it's high time I learned what it all means

[root@n2 log]# dig +short soa xdroop.com
n1.gridway.net. info.gridway.net. 2019050703 86400 3600 604800 7200
The numeric values are: SOA Value Name Description
2019050703 Zone serial number Nameserver will not use new versions of this zone if the presented serial number is less than the currently used value.
86400 Refresh Slave nameservers will try to pull an updated copy of the zone from the master every <Refresh> seconds.
3600 Retry If a slave's transaction with a master fails for some reason, the slave will try again in <Retry> seconds.
604800 Expire The maximum amount of time that a slave will keep a zone cached if it can't talk to the master.
7200 TTL This is the amount of time that negative answers are to be cached on downstream nameservers. Needs to be lower for zones that need to propagate quickly.