See the attached image for details.
Sorry, sorry. It had to be said… ok, so it didn’t, but still – they’re clogging up MY inbox, I can tell you THAT for sure!
The overhead is horrible for internal LANs as well – a friend who shall remain nameless is currently battling the ‘good’ virus – it saturated the network by having every machine download a 10M file (nearly sequentally), install, and now they’re all pinging across the whole of the interweb™ looking for others to patch.
For those interested, the above is a graph generated with MRTG with the help of mailscanner, and a specific configuration script. I’m just letting it filter everything for the time being – for the obvious reasons of trying to keep my sanity.