You can set up automatic forwarding of all email to an external mail account anywhere on the Internet. This is sometimes known in Unix parlance as a ''.forward'' - file.
It is configured using the mail sorting/filtering functions which are part of the Citadel system. The easiest way to configure it is to use WebCit:
In the above configuration, all mail will be sent to the forwarding address. It will not be kept in your Citadel inbox. If you would like to keep incoming mail in your Citadel inbox in addition to forwarding it, you need only add one extra rule.
Obviously this only demonstrates a small fraction of the things you can do with the sorting/filtering system. It also lets you sort and filter based on headers, message size, etc. If you add those kind of rules, you might choose to add them before your forwarding rule, so only the messages which don't get sorted are forwarded, or after your forwarding rule, so messages get sorted in addition to being forwarded. There is no limit to the possible configurations.