Hi guys!

I'm using dovecot submission server for clients to send emails and relay them to postfix. Everything works fine unless a client tries to send large (40Mbs) messages. No big deal one can say just set "message_size_limit = 314572800" in postfix and it should just work, but no, it does not, client gets "552 5.2.3 Message size exceeds administrative limit.". I've increased verbosity for smtpd process and get this logs for a failed attempt

Sep 12 13:43:21 mx10 postfix/smtpd[73602]: connection established
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: master_notify: status 0
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: name_mask: resource
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: name_mask: software
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: watchdog_start: 0x563f80b341b0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: time left   5 for 0x7fdef6cf4700 0x563f80b393d0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: time left   5 for 0x7fdef6cf4700 0x563f80b1ee10
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: time left 100 for 0x7fdef6d56b20 0x0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: time left 1000 for 0x7fdef6cf4720 0x563f80b1ee10
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: time left 1000 for 0x7fdef6cf4720 0x563f80b393d0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: select_delay 0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: timer 0x7fdef6cf4700 0x563f80b393d0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: rewrite stream disconnect
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_disable_readwrite: fd 20
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_cancel_timer: 0x7fdef6cf4700 0x563f80b393d0 -1
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_cancel_timer: 0x7fdef6cf4720 0x563f80b393d0 985
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: timer 0x7fdef6cf4700 0x563f80b1ee10
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: proxymap stream disconnect
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_disable_readwrite: fd 10
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_cancel_timer: 0x7fdef6cf4700 0x563f80b1ee10 -1
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_cancel_timer: 0x7fdef6cf4720 0x563f80b1ee10 985
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: watchdog_stop: 0x563f80b341b0
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: watchdog_start: 0x563f80b341b0
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: connect from localhost[127.0.0.1]
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: time left  85 for 0x7fdef6d56b20 0x0
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_list_match: localhost: no match
Sep 12 13:43:21 mx10 postfix/smtpd[73615]: event_loop: select_delay 85
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_list_match: 127.0.0.1: no match
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_list_match: localhost: no match
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_list_match: 127.0.0.1: no match
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: smtp_stream_setup: maxtime=300 enable_deadline=0
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_hostname: smtpd_client_event_limit_exceptions: localhost ~? 127.0.0.0/8
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_hostaddr: smtpd_client_event_limit_exceptions: 127.0.0.1 ~? 127.0.0.0/8
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 220 mx10 ESMTP Postfix (Debian/GNU)
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: watchdog_pat: 0x5609a03c01b0
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: vstream_fflush_some: fd 10 flush 47
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: vstream_buf_get_ready: fd 10 got 21
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: < localhost[127.0.0.1]: EHLO mx10
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_list_match: localhost: no match
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: match_list_match: 127.0.0.1: no match
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-mx10
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-PIPELINING
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-SIZE 314572800
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-VRFY
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-ETRN
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-ENHANCEDSTATUSCODES
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-8BITMIME
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250-DSN
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 250 CHUNKING
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: watchdog_pat: 0x5609a03c01b0
Sep 12 13:43:21 mx10 postfix/smtpd[73602]: vstream_fflush_some: fd 10 flush 138
Sep 12 13:43:22 mx10 postfix/smtpd[73602]: vstream_buf_get_ready: fd 10 got 6
Sep 12 13:43:22 mx10 postfix/smtpd[73602]: < localhost[127.0.0.1]: QUIT
Sep 12 13:43:22 mx10 postfix/smtpd[73602]: > localhost[127.0.0.1]: 221 2.0.0 Bye

looks like submission server just quits

if I configure imap client /Thunderbird to connect directly to postfix everything works just fine.

doveconf -n output is attached just in case