I'm not sure what to make of it at this point then. tcp connections can be be established to and from the jail. Yet apache is logging no access attempts, which is suspicious. I am (mostly) ruling out an apache configuration problem because you say you have changed only LogLevel following the package install; and in any case we should see chatter in at least the error log.
I think what I'd do next is:
- check /var/log/messages for NIC complaints;
- try viewing the welcome page from a different workstation (and different browser - e.g. lynx);
- and if all else fails, try running a different service - e.g. ftpd - within the jail (does it work or not?)
Finally, it doesn't seem like a network misconfiguration is the culprit, but it would be a good idea to post the output of
% ifconfig from the host, and also your jail-related directives in rc.conf on the host.