DNS expiry time

@pixelpadre:

Am I the only one to notice that the dns cache time is a startling 1209600 seconds or 14 days?

Maybe you are confusing SOA EXPIRE with with TTLs of RRsets and/or SOA MINIMUM, which are used for caching servers?

To clarify, the SOA EXPIRE field, where Linode uses a default of 1209600 seconds (14 days), specifies how long an authoritative server with a slave zone is allowed to keep serving the data without having successfully refreshed.

14 days in the range of values I would consider normal, if anything it's on the short side. That said, if you use the Linode nameservers alone, it seems unlikely that the expire value will matter in practice.

The default TTL used by Linode is 86400 (24h) and the SOA MINIMUM is likewise 86400.

Time in seconds that a secondary name server will treat its zone file as valid when the primary name server cannot be contacted. If your primary name server goes offline for some reason, you want the secondary name names to keep answering DNS queries for your domain until you can get the primary back online. Make this value too short and your domain will disapear from the Internet before you can bring the primary back online. A good value would be something between 2 weeks (1209600 seconds) and 4 weeks (2419200 seconds).

@pixelpadre:

Time in seconds that a secondary name server will treat its zone file as valid when the primary name server cannot be contacted. If your primary name server goes offline for some reason, you want the secondary name names to keep answering DNS queries for your domain until you can get the primary back online. Make this value too short and your domain will disapear from the Internet before you can bring the primary back online. A good value would be something between 2 weeks (1209600 seconds) and 4 weeks (2419200 seconds).

Ok, if we are on the same page regarding what this value means, care to elaborate on what makes it "startling"?

@hawk7000:

@pixelpadre:

Time in seconds that a secondary name server will treat its zone file as valid when the primary name server cannot be contacted. If your primary name server goes offline for some reason, you want the secondary name names to keep answering DNS queries for your domain until you can get the primary back online. Make this value too short and your domain will disapear from the Internet before you can bring the primary back online. A good value would be something between 2 weeks (1209600 seconds) and 4 weeks (2419200 seconds).

Ok, if we are on the same page regarding what this value means, care to elaborate on what makes it "startling"?

After further research I saw that it was normal. LeafDNS told me it was way to high and flagged it as a warning.

Does it? I tested a domain with that field set to 2678401 and it didn't complain.

(It complained about half a dozen other intentional decisions, though.)

http://leafdns.com/index.cgi?testid=A057C125

You are correct..its the DEFAULT TTL value of 86400 and recommends a lower value of 3600-10800. Highlighted field wasnt very obvious early this morning.

@pixelpadre:

You are correct..its the DEFAULT TTL value of 86400 and recommends a lower value of 3600-10800. Highlighted field wasnt very obvious early this morning.

Ah. That makes sense.

I'd generally call anything from about 300 (5 minutes) to 86400 (1 day) an acceptable default setting.

You may prefer to change it to 3600 - 10800, or something outside that range, but I don't think any of the above are generally terrible options.

I dont see where that is an option on linode dns manager

@pixelpadre:

I dont see where that is an option on linode dns manager

At the top of the page is the SOA Record section. Click "Settings" on the right to edit the default TTL.

You can also click "Edit" on any other record and change its TTL.