Hey there, just moved my IPB community to a freshly built Ubuntu LAMP and noticed that the number of active users on the site has halved to about 50ish.

Only been live like an hour but at this time of day Im used to seeing about 100+ users so Im concerned that a config somewhere within the server is limiting the number of connections, anyone aware if a default Ubunutu installation limits web connections this low?

DNS propagation takes time. If you just moved here from another host a couple of hours ago, some people might still be trying to access your site at the old location.