[Mailman-Users] Migration to a new server: recommendations for testing the new Mailman server before changing DNS records; also how to avoid lost/bounced messages during change-over?

[Mark Sapiro]

On 07/08/2013 01:29 PM, David wrote:
> On Thu, Jul 4, 2013 at 10:49 PM, Mark Sapiro <mark at msapiro.net> wrote:
> 
>     If the mail server on the new box thinks list domains are in its local
>     delivery space (mydestination in Postfix), you can just send mail from
>     an MUA on the local box configured to deliver via SMTP to the local MTA,
>     and it all should work except that mail from Mailman to local addresses
>     will be delivered to the new box instead of the current live box.
> 
> 
> The new box has no GUI. The OS is Debian 6.
> $ uname -r
> 3.9.3-x86_64-linode33
> 
> The MUA is:
> heirloom-mailx
> $ mailx -V
> 12.5 6/20/10
> 
> The MTA is postfix. (For some reason I can't run "postconf -d | grep
> mail_version" so I'll have to ask the sysadmin later about that. But at
> the moment, I don't know the postfix version.)
> 
> Given that info, which settings changes should I make to proceed with
> the testing plan you described above?
> 
> So far all I did was:
> 1. create a ~/.mailrc file with contents:
> 
> set smtp=localhost


If that tells mailx to send via smtp to localhost, that's good.


> 2. edit /etc/postfix/main.cf <http://main.cf> and change mydestination
> to the line below:
> mydestination = localhost, localhost.localdomain


If I understood correctly, this is not what you want. My understanding
is you have an old (current) box with a domain and an IP and DNS for the
domain pointing to the IP, and after the switch the domain and IP will
be those of the new box, but for now, the new box has a different IP.

If this is the case, you should not be making any changes to main.cf
over what you want after the switch, i.e. it should look like that on
the old box.

Now, in this configuration, list mail should be delivered locally, so if
you send mail from the local MUA on the new box to a list address, the
MUA will deliver it to the local Postfix and that in turn will deliver
it to the local Mailman.

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan