The simplicity of SMTP mail can be combined with t he robustnessof the sendmail MTA program and misused in numerous ways to create extraordinary and p o werful e-mail bombs. These e-mail bombs can be launched in many different a ttack scenarios which can easily ood and s h ut d o wn chains of SMTP mail servers. Sendmail-based SMTP mail relays also can be used covertly to distribute m essages and les that could be very damaging t o t he i n tegrity a n d brands of victims. This paper discusses mail-bombing t echniques, automated attack t ools, and countermeasures. Also discussed is an actual Internet based attack t hat w as launched in 1997 on the Langley AFB SMTP e-mail infrastructure. We also present a n a n alysis of the cyber-attack, graphs illustrating t he a ttack-volume, and a s t atistical e-mail bomb early-warning system.