Moved hosting, but some email randomly going to old host

we updated DNS servers, and have an alternate domain name at the old hostin

[nigelt74]

About 50 hours ago I set the domains DNS servers to point to the new hosting, and I realise it takes time to propagate through the net.
The old hosted site has an alternate domain pointed at it, as we want to keep it accessible till the new site is 100%, the alternate domain wasn't known to the customers.

But the weird problem i am having is that, emails to the site for the shifted domain (the one that is pointing to the new hosting), some are going to the old hosting, and before you say it, yes i know it is to be expected whilst the DNS change is propagated out.

However I have been communicating with the customer via email, and 90% of my emails are going to the new server, but the odd one goes to the old server, and thats whats confusing me 10 emails will go to the new server then suddenly one won't arrive and we check the old server and there it is, all by its lonesome in the inbox.

and also emails to the client from her customers some seem to go to the new server while others go to the old server and these customers can be using the same ISP

is this normal and will decrease over time.

anything i should be doing?

[lammert]

What TTL times did you use for the MX records of the domain before the switch? If the MX records had a TTL time of one or a few days, it will take at least that long before the old entries start to timeout in the caches of caching DNS servers around the world. And there is a small fraction of DNS servers--especially those serving networks behind a slow Internet connection--which don't use the TTL times you defined but have their own timeout policy.

[nigelt74]

That could explain it, as i am located in New Zealand and our broadband network is slow by international standards.

Thanks for that, its not something i even knew to check

[nigelt74]

And it gets odder, now even more email is going to the old server,

where would I check these ttl times

[lammert]

The TTL times are in the DNS record settings. You could either see them in the DNS server configuration file/panel, or on your local computer.

If you have access to a Windows computer, open a command prompt and type the following command:

nslookup

Inside the nslookup program, type the following three commands:

set debug
set type=MX
example.com

This will show you the currently distributed MX records together with the TTL times assigned. The nslookup command is also available under Linux, but it doesn't seem to tell you the TTL times in debug mode.

[phranque]

typically you would use nslookup and query the MX record, although it may be too late to see the values from your previous DNS configuration.