My MTA is behind my firewall, it sends SMTP to my public mail server,
which relays (smart host) via relay1.thorcom.net.
Relay1.thorcom.net is Devuan 4 Chimaera with Exim 4.94.2 built from source:
root@relay1:/var/log/exim# exim --version
Exim version 4.94.2 #2 built 04-Jan-2022 14:20:39
Copyright (c) University of Cambridge, 1995 - 2018
(c) The Exim Maintainers and contributors in ACKNOWLEDGMENTS file, 2007
- 2018
Berkeley DB: Berkeley DB 5.3.28: (September 9, 2013)
Support for: crypteq iconv() IPv6 Perl OpenSSL move_frozen_messages
Content_Scanning DKIM DNSSEC Event OCSP PIPE_CONNECT PRDR SPF
TCP_Fast_Open Experimental_SRS
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch dbm dbmjz
dbmnz dnsdb mysql passwd
Authenticators: plaintext
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile/maildir/mbx autoreply pipe smtp
Malware: f-protd f-prot6d drweb aveserver fsecure kavdaemon sophie clamd
mksd avast sock cmdline
Fixed never_users: 0
Configure owner: 0:0
Size of off_t: 8
Configuration file is /etc/exim/exim.conf
Smaller text-only emails to Gmail users work fine. Attach a full HD
image (1920 x 1080 Jpeg) and the message ends up being around 980K in
size, when I attempt to send it it stalls on relay1.thorcom.net.
Logs on relay1.thorcom.net show incoming from my server (mail.tubby.org)
just fine:
%20-->%20mail.tubby.org%20(Linux/Exim)%20-->%20%0A>%20relay1.thorcom.net%20(Linux/Exim)%20-->%20Gmail%0A>%20%0A>%20My%20MTA%20is%20behind%20my%20firewall,%20it%20sends%20SMTP%20to%20my%20public%20mail%20server,%20%0A>%20which%20relays%20(smart%20host)%20via%20relay1.thorcom.net.%0A>%20%0A>%20Relay1.thorcom.net%20is%20Devuan%204%20Chimaera%20with%20Exim%204.94.2%20built%20from%20source:%0A>%20%0A>%20root@relay1:/var/log/exim#%20exim%20--version%0A>%20Exim%20version%204.94.2%20#2%20built%2004-Jan-2022%2014:20:39%0A>%20Copyright%20(c)%20University%20of%20Cambridge,%201995%20-%202018%0A>%20(c)%20The%20Exim%20Maintainers%20and%20contributors%20in%20ACKNOWLEDGMENTS%20file,%202007%20%0A>%20-%202018%0A>%20Berkeley%20DB:%20Berkeley%20DB%205.3.28:%20(September%C2%A0%209,%202013)%0A>%20Support%20for:%20crypteq%20iconv()%20IPv6%20Perl%20OpenSSL%20move_frozen_messages%20%0A>%20Content_Scanning%20DKIM%20DNSSEC%20Event%20OCSP%20PIPE_CONNECT%20PRDR%20SPF%20%0A>%20TCP_Fast_Open%20Experimental_SRS%0A>%20Lookups%20(built-in):%20lsearch%20wildlsearch%20nwildlsearch%20iplsearch%20dbm%20dbmjz%20%0A>%20dbmnz%20dnsdb%20mysql%20passwd%0A>%20Authenticators:%20plaintext%0A>%20Routers:%20accept%20dnslookup%20ipliteral%20manualroute%20queryprogram%20redirect%0A>%20Transports:%20appendfile/maildir/mbx%20autoreply%20pipe%20smtp%0A>%20Malware:%20f-protd%20f-prot6d%20drweb%20aveserver%20fsecure%20kavdaemon%20sophie%20clamd%20%0A>%20mksd%20avast%20sock%20cmdline%0A>%20Fixed%20never_users:%200%0A>%20Configure%20owner:%200:0%0A>%20Size%20of%20off_t:%208%0A>%20Configuration%20file%20is%20/etc/exim/exim.conf%0A>%20%0A>%20%0A>%20Smaller%20text-only%20emails%20to%20Gmail%20users%20work%20fine.%20Attach%20a%20full%20HD%20%0A>%20image%20(1920%20x%201080%20Jpeg)%20and%20the%20message%20ends%20up%20being%20around%20980K%20in%20%0A>%20size,%20when%20I%20attempt%20to%20send%20it%20it%20stalls%20on%20relay1.thorcom.net.%0A>%20%0A>%20Logs%20on%20relay1.thorcom.net%20show%20incoming%20from%20my%20server%20(mail.tubby.org)%20%0A>%20just%20fine:%0A>%20%0A>%202022-03-13%2019:13:03%20CONNECT:%20Accepting%20connection%20from:%20%0A>%202a02:8010:7010::6700%20-%20not%20blocked%20by%20any%20RBL%0A>%202022-03-13%2019:13:03%20HELO:%20Accepted%20HELO/EHLO%20mail.tubby.org%20from%20remote%20%0A>%20host:%202a02:8010:7010::6700%0A>%202022-03-13%2019:13:03%20CRYPTO:%20Client%202a02:8010:7010::6700:47210%20issued%20%0A>%20STARTTLS%0A>%202022-03-13%2019:13:03%20HELO:%20Client%202a02:8010:7010::6700:47210%20using%20%0A>%20SSL/TLS%20cipher:%20TLS1.3:TLS_AES_256_GCM_SHA384:256%0A>%202022-03-13%2019:13:03%20HELO:%20Accepted%20HELO/EHLO%20mail.tubby.org%20from%20remote%20%0A>%20host:%202a02:8010:7010::6700%0A>%202022-03-13%2019:13:03%20MAIL:%20SPF%20Result=pass%20(tubby.org%20/%20(mail.tubby.org)%20%0A>%20%5B2a02:8010:7010::6700%5D)%0A>%202022-03-13%2019:13:03%20H=(mail.tubby.org)%20%5B2a02:8010:7010::6700%5D%20Warning:%20%0A>%20MAIL:%20TLS-STATUS%20Sender%20domain=tubby.org%20Host=(mail.tubby.org)%20%0A>%20%5B2a02:8010:7010::6700%5D%20using%20TLS%20cipher=TLS1.3:TLS_AES_256_GCM_SHA384:256%0A>%202022-03-13%2019:13:04%201nTTeJ-0001Tn-AC%20H=(mail.tubby.org)%20%0A>%20%5B2a02:8010:7010::6700%5D%20Warning:%20DKIM%20START:%20domain=tubby.org%20%0A>%20possible_signer=tubby.org%20status=pass%0A>%202022-03-13%2019:13:04%201nTTeJ-0001Tn-AC%20H=(mail.tubby.org)%20%0A>%20%5B2a02:8010:7010::6700%5D%20Warning:%20MIME:%20Type=multipart/mixed%20Size=931%0A>%202022-03-13%2019:13:04%201nTTeJ-0001Tn-AC%20H=(mail.tubby.org)%20%0A>%20%5B2a02:8010:7010::6700%5D%20Warning:%20MIME:%20Type=text/plain%20Size=1%0A>%202022-03-13%2019:13:04%201nTTeJ-0001Tn-AC%20H=(mail.tubby.org)%20%0A>%20%5B2a02:8010:7010::6700%5D%20Warning:%20MIME:%20Type=image/jpeg%20Size=688%20%0A>%20(Filename=IMG_0612.jpg)%0A>%202022-03-13%2019:13:05%201nTTeJ-0001Tn-AC%20<=%20mike@???%20%0A>%20H=(mail.tubby.org)%20%5B2a02:8010:7010::6700%5D%20P=esmtps%20%0A>%20X=TLS1.3:TLS_AES_256_GCM_SHA384:256%20CV=no%20S=954453%20DKIM=tubby.org%20%0A>%20id=4b53323e-feba-2b43-11df-adadac2ff6d8@???%20T=%22Michelle%202%22%0A>%20%0A>%20Exim%20logs%20the%20incoming%20message%20%22<=%22,%20the%20message%20ends%20up%20on%20the%20spool%20%0A>%20and%20is%20visible%20with%20mailq.%0A>%20%0A>%20There%20are%20no%20obvious%20signs%20that%20Exim%20is%20trying%20to%20complete%20the%20delivery,%20%0A>%20i.e.%20no%20%22=>%22%20and%20after%20a%20period%20(several%20minutes)%20it%20logs:%0A>%20%0A>%202022-03-13%2019:47:53%201nTTGO-0001Jw-Tr%20H=alt2.gmail-smtp-in.l.google.com%20%0A>%20%5B2a00:1450:4025:c03::1a%5D:%20SMTP%20timeout%20after%20sending%20data%20block%20(476909%20%0A>%20bytes%20written):%20Connection%20timed%20out%0A>%20%0A>%20%0A>%20So,%20what's%20occurring%20here?%C2%A0%20Does%20google/gmail%20have%20indigestion?%0A>%20%0A>%20%0A>%20Mike%0A>%20%0A>%20%0A>%20 "Reply to this message")
