Know the Facts. Stevens suggests configuring mail servers to only process mail sent by a local user or intended for delivery to a local user. Although helpful, this configuration is still not enough to deter a would-be spammer. Included in header line information should be the hostname the connecting computer provides in its HELO line, the IP address of that machine, and a reverse DNS lookup on that IP address. Keeping logs for any longer can have its problems, warns Knight.
Log files slow down the server.
We only have 153 gigs and 83 gigs are log files. In no time I'd run out of space. Being proactive doesn't mean you can be assured a spam-free existence, it just reduces your chances. If you are spammed, your Acceptable Use Policy may be your best weapon. SparkNET updates their Acceptable Use Policy every month.