Hello, The default value is good enough and may not need changing. As you said that frequent changes have to be made then configuring TTL of lesser value is OK. Id recommend you leave it at default value and monitor it, then decrease the value in case of problems. Thanks Zhang

as TTL with DNS defines how long an entry is valid when cached, lowering the TTL makes clients/nameservers further down from the authoritive dns server refresh the entry more often. you get higher accuracity at the cost of more network traffic.

as TTL with DNS defines how long an entry is valid when cached, lowering the TTL makes clients/nameservers further down from the authoritive dns server refresh the entry more often. you get higher accuracity at the cost of more network traffic.

How much is lesser? Are you recommending using windows server 2003 built-in monitoring program to monitor? And waht are the thing i should look at in the built-in monitoring program?

As cheers zhang mentioned from above, you also agree that i should leave the TTl default value? Lowering the TTL makes clients/nameservers further down from the authoritive dns server refresh the entry more often. you get higher accuracity at the cost of more network traffic. You mean the cached record file will be deleted more often, and if a client computer request the same website again their computer will request again to DNS server to get the IP Address fo that website again that cause more traffic? But if i increase the TTL value too much the DNS server / Client computer will stored too much cached record file that eventually will slow down the computer performance?

As cheers zhang mentioned from above, you also agree that i should leave the TTl default value? Yes.I do not represent the organisation I work for, all the opinions expressed here are my own. This posting is provided "AS IS" with no warranties or guarantees and confers no rights. - .... .- -. -.- ... --..-- ... .- -. - --- ... ....

If you have something at IP A that you want to provide service from and IP A becomes unavailable and you want to provide service now from IP B, then a lower TTL value will effect that change more quickly. in that scenario if you change your DNS entry from A to B, you will have to wait for up to the time period specified in the TTL for the change to be globally effective. some solutions use DNS for failover of components and in that case TTLs are generally low to speed the failover process.Doug Kentner

If you have something at IP A that you want to provide service from and IP A becomes unavailable and you want to provide service now from IP B, then a lower TTL value will effect that change more quickly. in that scenario if you change your DNS entry from A to B, you will have to wait for up to the time period specified in the TTL for the change to be globally effective. some solutions use DNS for failover of components and in that case TTLs are generally low to speed the failover process.Doug Kentner

Good scenario, but i don't know how to setup the configuration in DNS server with the computer A and Computer B. Do i just open DNS server MMC and create computer A and computer B " A Record " and may be change the TTL value if i know computer A will be unavailable for 1 day let's say?

stuckFree, would you mind explaining, what exactly would you like to achieve out of changing TTL values ? If you can share the details, that would help us to provide relevant suggestions. Also, as Meinolf stated in his reply above, please consider creating a new thread in Network Infrastructure Servers forum for network services specific questions http://social.technet.microsoft.com/Forums/en/winserverNIS/threadsI do not represent the organisation I work for, all the opinions expressed here are my own. This posting is provided "AS IS" with no warranties or guarantees and confers no rights. - .... .- -. -.- ... --..-- ... .- -. - --- ... ....

As cheers zhang mentioned from above, you also agree that i should leave the TTl default value? You mean the cached record file will be deleted more often, and if a client computer request the same website again their computer will request again to DNS server to get the IP Address fo that website again that cause more traffic? But if i increase the TTL value too much the DNS server / Client computer will stored too much cached record file that eventually will slow down the computer performance? pretty much yes to both. unless you have a specific scenario you want to address, the default value will be ok. for a scenario: lets say its monday and you have a website hosted on 10.10.10.10 and you know that host will be maintained on friday. now you lower the ttl for that websites name to say 10 mins. other nameservers will pick this ttl up till friday. traffic increases, but now, on friday, you change your websites dns entry to 10.10.10.20, which hosts a maintenance site, and clients will land on that maintenance site within 10 minutes max, so you can start your actual maintenance after 10 mins. if ttl would be higher, it could be clients try to reach the shut down site as they have still the cached entry for the old ip.

What preferably value for TTL for each resource record?

For Details, pls refer following Time-to-Live (TTL) Values http://www.zytrax.com/books/dns/apa/ttl.html Changing TTLs http://docstore.mik.ua/orelly/networking_2ndEd/dns/ch08_04.htm Resource Record Types http://technet.microsoft.com/en-us/library/cc958958.aspxI do not represent the organisation I work for, all the opinions expressed here are my own. This posting is provided "AS IS" with no warranties or guarantees and confers no rights. - .... .- -. -.- ... --..-- ... .- -. - --- ... ....

Hello, The default value is good enough and may not need changing. As you said that frequent changes have to be made then configuring TTL of lesser value is OK. Id recommend you leave it at default value and monitor it, then decrease the value in case of problems. Thanks Zhang

Hello, for network services specific questions please ask in the following forum http://social.technet.microsoft.com/Forums/en/winserverNIS/threadsBest regards Meinolf Weber MVP, MCP, MCTS Microsoft MVP - Directory Services My Blog: http://msmvps.com/blogs/mweber/ Disclaimer: This posting is provided AS IS with no warranties or guarantees and confers no rights.