DNS Caching under OS 8/9

thoule

Registered
Hi- users here connect to our mail servers by conneting to username.mail.wesleyan.edu, where username is thier logon name. This way, we can add/change mail servers when we want to without reconfiguring the user's computers.

However, the macs seem to be trying to connect to the old servers even after we change the DNS names to point to the new server. I think that Open Transport is caching the IP name of the old mail server.

My question is- how long until this cached name expires? Also, can I force the macs to expire the DNS cache?

Thanks for the help!
-todd-
 
I may be completely wrong, but I believe the DNS cache is stored in memory. The expiration time should be the TTL (time to live) coming from the name server (Apple's developer docs don't have a whole lot to say on the issue). So, perhaps the TTL should be reduced on your DNS server. Of course, I suppose if this was the source of the problem, you would see the same behavior on other clients, not just Macintoshes.

Do the Macs try to connect to the wrong server even after a reboot? If so, they are obviously caching to disk and not to memory, and I am completely wrong. Another possibility (although very remote) is that some of your users have created hosts files that include the old mail server host names and IP addresses. Look for a file called "hosts" in the System folder.
 
Thanks for the reply D- The problem lasted about 2 days even with several restarts. So I guess we know how Apple handle's it's caching... I'm not sure how to get around the problem next time though... For my users, two days without email is a major problem.
-t-
 
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