At 2:21 PM -0400 8/8/02, Neil Herber wrote: >It is rumored that on or about 2002-08-08 10:58 AM -0700, Thomas >Tempelmann wrote as follows: >>Thoughts on 2: >> >> Here I will have to change NS records. I wonder how I >>do this in a way that I have hardly any outage (I run a >>few mailing lists, and they should not black out too long >>because of this). Let's assume I can get the software and >>hardware moved to the new location in a second. Then what >>would be the best way to make all SMTP servers that want >>to send mail to my server will find the server at the new >>location right away? > >I'm no DNS expert, but what if you IMMEDIATELY made the new IP >number your primary mail server and demoted the current IP to >secondary. > >After a few days the entire world will know what your primary is, >but will continue delivering mail to the secondary since the primary >doesn't exist yet. > >In your 2 second swap, the secondary will disappear and the primary >will pop up ready to go. Close to zero down time. > >TADA! > >Waiting to be corrected by the real experts ... ;->
This is correct, though it's basically not that complicated. If you have a secondary mail server, and it refers to the same DNS server as your primary mail server, then as long as you don't take down both servers at the same time, you're fine. When your primary mail server is down, mail goes to the secondary, and when the primary comes back up and you change DNS to point to it, the secondary will deliver mail to the primary, and nothing is lost. The rest of the planet doesn't have to really know what's going on. (Just don't put a mail server for different domains on the old IP right away.) Normally, of course, if you are planning a major change to your domain, shortening the TTL a week ahead is a good idea. But if you do the mail server migration correctly, even this isn't necessary. >-- >Neil > >Neil Herber, RGD >Corporate info at http://www.eton.ca/ >Eton Systems, 15 Pinepoint Drive, Nepean, ON, Canada K2H 6B1 >Tel: (613) 829-4668 > > >############################################################# >This message is sent to you because you are subscribed to > the mailing list <[EMAIL PROTECTED]>. >To unsubscribe, E-mail to: <[EMAIL PROTECTED]> >To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> >To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]> >Send administrative queries to <[EMAIL PROTECTED]> -- Alex von Thorn Aurora Award nomination 2002: Fan Writing http://worldhouse.com/alex/ Deputy Head of Programming, Torcon III http://www.torcon3.on.ca/ Vice-Chair, Seattle in '05 NASFiC bid http://www.seattle2005.org/ ############################################################# This message is sent to you because you are subscribed to the mailing list <[EMAIL PROTECTED]>. To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]> Send administrative queries to <[EMAIL PROTECTED]>
