On mail.quux, a node of NNCPNET (the NNCP-based peer-to-peer email network), I started noticing emails not being delivered. They were all in the queue, frozen, and Exim’s log had entries like: unable to set gid=5001 or uid=5001 (euid=100): local delivery to [redacted] transport=nncp Weird. Stranger still, when I manually ran the queue with sendmail -qff … Continue reading A Mail Delivery Mystery: Exim, systemd, setuid, and Docker, oh my!→
