My IP block has been delisted by SpamHaus. Unfortunately, in spite of the “R” in “RBL” standing for “Real-time”, apparently some ISPs cache their copy of the SpamHaus RBL and are still blocking me. Hopefully normal service will be restored eventually. My outgoing mail queue has gone from 120 to 85, so I guess some ISPs are updating their caches.
I also discovered that evidently you can’t just rsync your whole mail spool area over to a new system because postfix somehow ties the spool file names to the inodes they’re on or something. I was getting strange errors like fatal: lock file defer B99792602A5: Resource temporarily unavailable until I did a “postfix check”, and it said something about renaming files, and now everything is happy again.