Huge Increase in POP3 Bandwidth Usage

[DaveSawers]

Over the last few days, my POP3 bandwidth usage has jumped from it's regular nominal usage to huge amounts that threaten to result in my hosting company disabling my account.

It seems this is incoming traffic, but I'm not certain. How do I diagnose what's happening and what can I do about it? The hosting uses WHM and CPanel.

I am fairly confident that the problem does not emanate from our computers here. We're up to date on virus protection, etc. and we haven't seen an increase in network traffic between us and our ISP.

[DaveSawers]

I deleted the e-mail accounts associated with the domain and recreated them using new passwords. Fortunately there are only two so this wasn't a big deal.

Since then, bandwidth usage has returned to normal. My hosting provider said this action was the correct first step and if it should recur then we can look at which IP addresses the traffic is coming from and consider blocking them.