I got a note today from another group member here saying they had problems sending emails. My ISP started to block tcp traffic to port 25 recently, after 15+ years of normal service. The spam I get got down to 0 for hours now, negligible for today; typically I get hundreds if not thousands of spam emails on two of my addresses combined. I tested sending between several of my emails, most hosted differently, and things worked but for one which has been erratic before; and it did get the first try, me manually smtp-ing into port 587 (ISP blocked port 25, remember; and tethering the house from the phone is a bit more of a hassle). Messages sent to intentionally invalid email addresses don't bounce, complete silence. The "Return-path:" of the messages I send containing one is replaced by a null path, <>. Formerly I did not put any return-path in my messages, they came across with something like <mailman-whatever...>, not an address but bouncing worked.
Has anyone noticed anything unusual along these lines?