Solved

What is the maximum TTL Value i can set for DNS Entries?

Posted on 2007-04-07
6
4,615 Views
Last Modified: 2012-06-27
What is the maximum TTL Value i can set for DNS Entries? Such as A, MX, CNAME ?

I'm more interested in an article describe it in more detail than just a number but either one would work.

thanks,
0
Comment
Question by:MichaelPro
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
6 Comments
 
LVL 16

Expert Comment

by:InteraX
ID: 18870325
Hello MichaelPro,

My O'Reily book on DNS & Bind appears to imply that the maximum TTL is 99,999,999 seconds. Approximately 3.1 years. Either that or 3,600,000 seconds, approx. 41 days. To know for definite, I would suggest reading the RFC's.

Regards,

InteraX
0
 
LVL 16

Accepted Solution

by:
InteraX earned 100 total points
ID: 18870331
MichaelPro,

Just found this.
8. Time to Live (TTL)

   The definition of values appropriate to the TTL field in STD 13 is
   not as clear as it could be, with respect to how many significant
   bits exist, and whether the value is signed or unsigned.  It is
   hereby specified that a TTL value is an unsigned number, with a
   minimum value of 0, and a maximum value of 2147483647.  That is, a
   maximum of 2^31 - 1.  When transmitted, this value shall be encoded
   in the less significant 31 bits of the 32 bit TTL field, with the
http://www.rfc-editor.org/rfc/rfc2181.txt
specified in 1997.

InteraX
0
 
LVL 16

Expert Comment

by:InteraX
ID: 18870333
MichaelPro,

That appears to imply 68 years!!! ;-)

InteraX
0
 
LVL 16

Assisted Solution

by:InteraX
InteraX earned 100 total points
ID: 18870340
InteraX,

Second reference

TTL             which is the time to live of the RR.  This field is a 32
                bit integer in units of seconds, an is primarily used by
                resolvers when they cache RRs.  The TTL describes how
                long a RR can be cached before it should be discarded.
http://www.faqs.org/rfcs/rfc1034.html

InteraX
0
 
LVL 4

Author Comment

by:MichaelPro
ID: 18870359
wow, thanks a lot for the information. i got pretty good idea!!! I'll increase the points and split among the participants.

-Michael
0

Featured Post

Salesforce Has Never Been Easier

Improve and reinforce salesforce training & adoption using WalkMe's digital adoption platform. Start saving on costly employee training by creating fast intuitive Walk-Thrus for Salesforce. Claim your Free Account Now

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Resolve DNS query failed errors for Exchange
I had an issue with InstallShield not being able to use Computer Browser service on Windows Server 2012. Here is the solution I found.
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…
Michael from AdRem Software outlines event notifications and Automatic Corrective Actions in network monitoring. Automatic Corrective Actions are scripts, which can automatically run upon discovery of a certain undesirable condition in your network.…

695 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question