Dyndns with custom DNS Service Sub-Domain Create?

In order to reach http://example.com/webmail through http://mail.example.com/ you have the following options:

• In case mail.example.com is behind a different IP address than example.com, simply add an A record for mail.example.com pointing to your related IP address. You need to have an A record for mail.example.com anyway, as you defined this in the MX record for example.com.

• You probably can control the behavior of mail.example.com by your web server software. Look out for virtual hosting or virtual server. With this feature you can define to what content a visitor is directed when using a certain (sub)domain name.

• Alternatively, make mail.example.com a WebHop Redirect cloaking http://example.com/webmail in a frame. But then you can't define it as MX destination any longer. (An MX record must point to a name having an A record. A WebHop Redirect however can't have an A record at the same time.)