A few hiccups with using the Zone Edit system for secondary mail services – the system I’d set up to block sites that send us lots of viruses was picking up the Zone Edit IPs and blocking them too – whoops. They’re now no longer being blocked and the mail is flowing again.
We’re still looking at an expensive month again though as there have been some spikes in our traffic. I’m still trying to get mrtg up and running so I can tell exactly where it’s all coming from…