[geofft]

I'm not familiar with session border controllers, but DCs can be and usually are placed somewhere at the apex of the domain, via SRV records.

If you really have trouble, you can tell your firewall to route ports 80 and 443 to another machine and everything else to the device you need. (I've run a hackier version of this that used netcat inside inetd: we didn't want a web server on the machine that owned the domain name, but there was another nearby web server cluster that we added a virtual host to. And we were fine running inetd and netcat on the machine.)

[seanp2k2]

I've done something similar but using iptables and dnsmasq to route DNS differently depending on where the requests were coming from and what domain they were asking about.