> I take it your mail provider uses Postfix and you claim it messes up? I never said what server software my ESP¹ uses. My mention of postfix referred to my own local host. I run postfix locally but it is not WAN-facing (thus all inbound mail is by fetchmail grabbing from pop3 servers).
¹ESP: email service provider But incidentally, you are correct. My ESP in fact also uses postfix. And they use the default setting, as you suggest: > The postconf(5) manual page (command: man 5 postconf) states: > > > empty_address_recipient (default: MAILER-DAEMON) > > So that's upstream business, they have the means to make that valid -- > and not fetchmail's business to fix. Indeed. It’s a bit surprising postfix would default to an RFC non-compliant value. And I suppose the take-away there is that my ESP is not doing something unusual, which means this scenario is more common than ideal. > Are you using multidrop? => > <https://www.fetchmail.info/fetchmail-FAQ.html#G3> $ env LC_ALL=C fetchmail -V | grep -i drop ^ this indicates single-drop mode is used for all my configs. > So please provide fetchmail -vv logs. To reproduce this, I had to attempt to send an oversized message to the same recipient as that of august last year. Luckily the same server limits are in place and nothing changed (which means my ESP has not fixed the problem on their end that I reported [annoying] -- but that actually benefits this reproduction to get more detailed logs). ===8<---------------------------------------- fetchmail: Trying to connect to 127.0.0.1/13552...connected. fetchmail: POP3< +OK [XCLIENT] howdy, ready. fetchmail: POP3> CAPA fetchmail: POP3< +OK fetchmail: POP3< CAPA fetchmail: POP3< TOP fetchmail: POP3< UIDL fetchmail: POP3< RESP-CODES fetchmail: POP3< PIPELINING fetchmail: POP3< AUTH-RESP-CODE fetchmail: POP3< STLS fetchmail: POP3< USER fetchmail: POP3< SASL PLAIN LOGIN fetchmail: POP3< . fetchmail: 127.0.0.1: WARNING: server offered STLS, but sslproto '' given. fetchmail: POP3> USER manny fetchmail: POP3< +OK fetchmail: POP3> PASS * fetchmail: POP3< +OK Logged in. fetchmail: selecting or re-polling default folder fetchmail: POP3> STAT fetchmail: POP3< +OK 1 4567 fetchmail: 1 message for manny at mannysESP-onion (4567 octets). fetchmail: POP3> LIST 1 fetchmail: POP3< +OK 1 4567 fetchmail: POP3> RETR 1 fetchmail: POP3< +OK 4567 octets fetchmail: reading message manny@127.0.0.1:1 of 1 (4567 octets)About to rewrite Return-Path: <MAILER-DAEMON>... ...rewritten version is Return-Path: <MAILER-DAEMON@127.0.0.1>. fetchmail: About to rewrite From: mailer-dae...@mx0.mannysesp.net (Mail Delivery System)... ...rewritten version is From: mailer-dae...@mx0.mannysesp.net (Mail Delivery System). fetchmail: About to rewrite To: myal...@mannysesp.net... ...rewritten version is To: myal...@mannysesp.net. fetchmail: Trying to connect to ::1/25...connected. fetchmail: SMTP< 220 gudrun ESMTP Postfix (Debian/GNU) fetchmail: SMTP> EHLO mannys.host fetchmail: SMTP< 250-gudrun fetchmail: SMTP< 250-PIPELINING fetchmail: SMTP< 250-SIZE 40960000 fetchmail: SMTP< 250-VRFY fetchmail: SMTP< 250-ETRN fetchmail: SMTP< 250-ENHANCEDSTATUSCODES fetchmail: SMTP< 250-8BITMIME fetchmail: SMTP< 250-DSN fetchmail: SMTP< 250-SMTPUTF8 fetchmail: SMTP< 250 CHUNKING fetchmail: forwarding to localhost fetchmail: SMTP> MAIL FROM:<MAILER-DAEMON@127.0.0.1> BODY=8BITMIME SIZE=4567 fetchmail: SMTP< 501 5.1.7 Bad sender address syntax fetchmail: SMTP error: 501 5.1.7 Bad sender address syntax fetchmail: SMTP> RSET fetchmail: SMTP< 250 2.0.0 Ok fetchmail: not flushed fetchmail: POP3> QUIT fetchmail: POP3< +OK Logging out. fetchmail: SMTP> QUIT fetchmail: SMTP< 221 2.0.0 Bye fetchmail: 6.4.37 querying mannysESP-onion (protocol POP3) at Wed 22 Jan 2025 02:22:22 PM CET: poll completed fetchmail: New UID list from mannysESP-onion: <empty> fetchmail: not swapping UID lists, no UIDs seen this query ===8<---------------------------------------- I should also elaborate on this line to clear up confusion: reading message manny@127.0.0.1:1 of 1 (4567 octets)About to rewrite Return-Path: <MAILER-DAEMON>... That looks as if the ESP is my localhost. But it’s not. There is a fetchmail limitation (unless I’m wrong) that fetchmail cannot handle onion hosts. So I have this config stanza: ===8<---------------------------------------- skip mannysESP-onion via 127.0.0.1 protocol pop3 port 13552 username "manny" sslproto '' fetchall ===8<---------------------------------------- So running fetchmail is complicated. I run fetchmail this way: ===8<---------------------------------------- $ socat TCP4-LISTEN:13552,reuseaddr,fork SOCKS4A:127.0.0.1:ungodlyverylongassonionversion3hostnamehere.onion:110,socksport=9050 & $ local pid=$! $ fetchmail -d0 mannysESP-onion $ kill "$pid" ===8<---------------------------------------- Fetchmail thinks it’s fetching from a local server, but 127.0.0.1:13552 is actually the end of a tunnel over Tor to an onion host. Hmm.. I just realized that may be why fetchmail decides to append @127.0.0.1 to MAILER-DAEMON.
