DNS TTL Time

[Shivkumar]

Dear Sirs,

Our web applications are configured for Geographic load balancing. In case one environment is not available, the traffic will route to another GeO.

My apprehension is, DNS has TTL time and it will hold the traffic for that period. I believe, in most of the environment DNS servers TTL time is 4 minute. That means switching over next
Geo will not be detected upto 4 minute.

Am i correct or misunderstood this concept ?

Thanks,
Shiv

[Arunvijai_4]

Hi Shiv,

TTL (Time To Live) is a limit on the period of time that a unit of data (e.g. a record) can exist before it is discarded also, Specifying the amount of time other DNS servers and applications are allowed to cache the record.

You can find more information about DNS TTL,

http://www.simpledns.com/help/index.html?df_ttl.htm

-Arun

[Yogeeraj_1 · Accepted solution]

hi Shiv,

Each domain name has one or more Resource Records (RRs) associated with it. Resource records are 5-tuples:
Domain_name TTL Type Class Value

TTL
is the Time To Live of this RR. When this RR is returned as a result of a DNS lookup, the remote host normally caches the information for efficiency. The TTL is the time, in seconds, after which the cached information should be regarded as potentially out of date.

Hence, a change will definitely help in your case.

kind regards
yogeeraj

[Arunvijai_4]

Hi Shiv,

Another good link about TTL concept,

http://www.zytrax.com/books/dns/apa/ttl.html

-Arun

[Muthukumar_5]

TTL is related caching the DNS recored informations.

Time To Live, the number of seconds remaining on a cached record before it is purged. For authoritative records the TTL is fixed at a specific length. If a record is cached, the server providing the record will provide the time remaining on the TTL rather then the original length it was given.

A good explanation. Refer here at http://www.menandmice.com/online_docs_and_faq/glossary/glossarytoc.htm?ttl.htm. Use hyper links to learn more.

--
Muthu