GSLB failover time

[alec.waters]

Hi,

When using GSLB, do the CSSs hand out DNS replies with a TTL of 0? Does this mean that every client makes a DNS request for every bit of content they need? e.g., for a web page with 10 images on it, would 11 DNS requests be made?

thanks a lot,

alec

[smalkeric]

The following documents might help you:

http://www.cisco.com/en/US/products/hw/contnetw/ps789/products_configuration_example09186a0080094964.shtml

http://www.cisco.com/en/US/products/hw/contnetw/ps789/products_configuration_example09186a00801dcd75.shtml

[mvoight · Accepted solution]

The ttl of 0 means that the device will cache it for its minimum cache time or not a all. The cache time will vary by client. It is also important to note that browser's may have a different minimum cache time than the operating system they run on. For instance, according to Microsoft Knowledge Base Article 263558 (Nov 2003) ,IE 4 and later, caches DNS for 30 minutes. In IE 3 and earlier, it was cached for 24 hours. This article tells you how you can adjust the DNS cache time out:

http://support.microsoft.com/default.aspx?scid=KB;en-us;263558&

Michael

[alec.waters]

Thanks Michael!

alec