https://bugs.exim.org/show_bug.cgi?id=2250
--- Comment #2 from David Carter <[email protected]> --- > I can see a steady stream of 'NULL character' error messages > which appear to relate to remote hosts attempting to talk gibberish > (TLS perhaps?) on port 25 Yes, we still see this now that I reverted to 4.89.1 (+security patch). However NULL characters appearing spuriously in the middle of genuine SMTP commands, for example. 2018-03-06 09:44:43 +0000 SMTP syntax error in "RCP? TO:<[email protected]>" H=lists-4.csi.cam.ac.uk [131.111.8.103]:57345 I=[131.111.8.137]:25 NULL character(s) present (shown as '?') only happens when I am running 4.90.1. Just to add: After a single "RCPT TO" is rejected with one of these 501 NULL characters are not allowed in SMTP commands errors, further recipients on the same SMTP transaction work just fine. I can't immediately find evidence of two separate "NULL characters" errors on a single SMTP transaction. However Mailman is capped at 500 recipients per message. After that point it breaks things up into multiple messages. Our mailing lists system has been running Exim 4.89 throughout: only the receiving end has changed. -- You are receiving this mail because: You are on the CC list for the bug. -- ## List details at https://lists.exim.org/mailman/listinfo/exim-dev Exim details at http://www.exim.org/ ##
