I track lots of things on my small mail server, and one of them is the
number of times my mail server accepts a connection on TCP/25 from a
remote server. This number has steadily risen from around 9,000 times
per week (several years ago) to about 14,000 times per week (this summer).
Recently, however, I've seen an explosion in the number of machines that
are connecting to me. Like double. Also, I am getting an astounding
amount of spam. I've done some analysis of my logs using perl, but
can't find anything obvious. Buddies that also run their own mail servers
are seeing similar jumps in volume. What's going on?