Hi, all: I know some of you use nullmailer for sending outgoing mail, but it *really* must be avoided, as the messages it sends are not RFC-2822 compliant. Per that RFC, header lines MUST NOT be longer than 998 characters in length, which is not something nullmailer appears to be paying any attention to. Some mailservers will outright reject messages with lines exceeding 998 characters (Exim), and some will force-insert <CR><LF><SPACE> at exactly character 998, regardless of what that does to the header: https://lore.kernel.org/linux-kernel/20240109171807.GA2783042-robh@xxxxxxxxxx/raw You will notice, that the enforced line-break cuts across the email address: Cc: [...] Sergey Shtylyov <s.shtyl yov@xxxxxx> A message with such header *may* get delivered, or it may get rejected due to malformed headers (e.g. Exim does that by default). Anyone then attempting to reply to such message will likely have trouble as well. Unfortunately, nullmailer appears to always re-parse To/Cc headers, so even if the original email properly wrapped the recipients headers before it was fed to nullmailer, everything will then just be concatenated into one long line: https://github.com/bruceg/nullmailer/blob/master/src/inject.cc#L384 I'll open an issue with nullmailer about this, but the project doesn't appear very alive, so your best bet is to switch to msmtp. It has msmtp-{enqueue,listqueue,runqueue} commands that will do everything nullmailer can do and won't break your mail. -K
