Assuming the only thing changing is the IP Address/host name for the SMTP
server:
No need to forward mail as long as you lower the TTL (Time To Live - I think -
my DNS and Bind book is at the office) on your domain and leave it there for a
period of time just longer than the current TTL. This way every server
everywhere will have checked back in with your DNS server and received the new
TTL. Assuming the server was caching your domain information. Now every server
everywhere will check in with your DNS server for changes if the new TTL time
has passed. Therefore if you set the new TTL time to some small time frame, say
15 minutes, even if your old server is not available on the first try the next
delivery attempt will see the new MX record in the DNS and send the mail to the
right server. The only thing you need to be conscious of is how long you have
no server available for SMTP. All SMTP servers will try to resend a mail
message if it fails the first time, second time and most a third time. Beyond
that things can be unpredictable, but all servers will wait some arbitrary time
frame before attempting to redeliver mail. This is why you want your TTL to be
low, hopefully in-between tries by sending SMTP servers. Be aware this will
cause an increase in traffic to your DNS server so it is wise to adjust your TTL
back to whatever your original setting was when you know mail is flowing
properly.
If I have thoroughly confused you feel free to e-mail me off list and I will
actually take some time to explain how it works rather than just typing off the
top of my head.
Cheers,
Kevin
Dustin Krysak wrote:
> Should I setup my old mail server to forward to my new one for a few days,
> in case any mail resolves to the old address? (Until all the DNS is
> updated.)
>
> -Dustin Krysak-
> Network Analyst
> Beamscope Canada Inc.
> Vancouver, BC
>
> -----Original Message-----
> From: Kevin Bull [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, April 25, 2000 10:33 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [IMail Forum] Best Way - Server Move
>
> Dustin,
>
> Prior to moving your mail files from one machine to the new machine be sure
> and
> change the DNS TTL on your domain. You should change it to something like
> 15
> minutes. Let that run for a period of time longer than your current DNS
> TTL.
> Then move the files and make the change to your DNS. After about an hour or
> so
> or longer if that is how long it takes for you to be satisfied that all is
> working, change the DNS TTL back to your original value.
>
> I did it just recently and it worked well for us.
>
> Hope it goes smoothly for you!
> Cheers,
>
> Kevin Bull
>
> Dustin Krysak wrote:
>
> > Hi everyone....
> >
> > Sorry for the repeated question (I know it has been covered here before -
> I
> > tend to sift through all the mail)...
> >
> > I'm moving my Mail services to a new machine/IP address....
> >
> > I'm curious as to what the best way is to handle this so that there is no
> > lost mail while the DNS updates itself through out the web....
> >
> > Thanks in advance
> > -Dustin Krysak-
> > Network Analyst
> > Beamscope Canada Inc.
> > Vancouver, BC
> >
> > Please visit http://www.ipswitch.com/support/mailing-lists.html
> > to be removed from this list.
>
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