SMTP migration help

Hi Guys,

Hope this is the right forum for this!

We want to move ISP, but host our own smtp email server (exchange).

In principle, we will get a migration code, get a date for migration, migrate, and then update the MX records for our domain to point at the new static IP our new ISP will give us.

What I can't figure out is, what is the best way to do this without losing any email? For example, if the migration is set for a Monday, do we:

1. Update our MX records on a Friday
2. On Monday assume that at the time of migration, the DNS records have fully propogated and by then when we do switch over, we'll probably have a few mails already waiting for us?

Would this then mean we need to ask our ISP to activate the static IP on say the Friday to catch any emails as/when the DNS propogation occurs?

Thanks!
Raj

Only thing I can suggest would be to go for a backup mail service, which will hold emails untill the change is complete...
Alternatively, most SMTP servers retry to send messages for 48 hours, so if the ISP change was scheduled for a Monday, change it on a Sunday, by the Monday DNS details should have propegated down so you should be up ad running with little hassle...

edit -

Your domain host may actually offer a backup mail service that you point your MX records to untill the changeover has been done...

Edited by deleted (Mon 10-Aug-09 12:55:52)

In reply to a post by abd08:

Hi Guys,

Hope this is the right forum for this!

We want to move ISP, but host our own smtp email server (exchange).

In principle, we will get a migration code, get a date for migration, migrate, and then update the MX records for our domain to point at the new static IP our new ISP will give us.

What I can't figure out is, what is the best way to do this without losing any email? For example, if the migration is set for a Monday, do we:

1. Update our MX records on a Friday
2. On Monday assume that at the time of migration, the DNS records have fully propogated and by then when we do switch over, we'll probably have a few mails already waiting for us?

Would this then mean we need to ask our ISP to activate the static IP on say the Friday to catch any emails as/when the DNS propogation occurs?

Thanks!
Raj

One thing that will help is changing the mx dns entry ttl from say 84000 down to say 3600 .

Not sure whether Exchange has an option to collect mail by POP from another server. If it does, you could have a 'backup' account with any old hosting firm (for under $10 a year, even) and use that as the second MX (sounds like you only have one, normally a bad idea) and while you are switching ISP, you could have just the one, ie the 'backup' to accept incoming mail, setting it as backup when everything complete and your new IP is being used as the first MX destination.

Unfortunately most cheap hosting seems to use only one mail server, so for my clients I tend to suggest a backup (!*) which can dump all incoming mail into a Google or Runbox mail account, so there's some guarantee of storage even if the office mail server isn't accessible (one client has two ADSL connections with different ISPs, and can switch, assuming it is during the working week. However, if something goes wrong and system admin (who has no PCs at home, and goes off rambling) isn't available. their incoming mail will definitely be stored rather than queued on sending servers, and can thus be checked by some key staff.

(*) in case their office link is down - it is not unknown for a digger to cause damage to hundreds of business lines in the middle of a city, taking some days to repair

Thanks for all the suggestions guys! I have gone with a Backup MX service (didn't realise these were so cheap!) and should be all sorted now

Thanks again!!
Raj