On Thu, Mar 15, 2018 at 11:30 AM, Haynes, Jonathan via Exim-users < exim-users@exim.org> wrote:
> Since upgrading to 4.90-1 every so often we get log messages of the > following form > > 2018-03-14 12:15:05 SMTP syntax error in "RCPT TO:<xxx?x...@cranfield.ac.uk>" > H=mail-wm0-f46.google.com [74.125.82.46] I=[138.250.49.234]:25 NULL > character(s) present (shown as '?') > 2018-03-14 23:25:04 SMTP syntax error in "RCPT TO:<XXXXXXX@cra?field.ac.uk>" > H=mail-qk0-f181.google.com [209.85.220.181] I=[138.250.49.234]:25 NULL > character(s) present (shown as '?') > 2018-03-09 10:56:00 SMTP syntax error in "R?PT TO:<xxxx...@cranfield.ac.uk>" > H=mail-yb0-f193.google.com [209.85.213.193] I=[138.250.49.234]:25 NULL > character(s) present (shown as '?') > 2018-03-07 10:21:52 SMTP syntax error in "BD?T 27127 LAST" H= > mail-it0-f66.google.com [209.85.214.66] I=[138.250.49.234]:25 NULL > character(s) present (shown as '?') > > > (I have masked the actual email addresses) > > So NULLs suddenly appear anywhere in the SMTP command, sometimes in the > email address, sometimes the verb etc. In every case the NULL is a > replacement for a real character not additional. When Exim sees these it > returns a 501 so if this is part of a RCPT command the sender gets an NDR. > It appears they are only coming in RCPT and BDAT commands but that may be > coincidence. There are not a huge number - it seems to be between 2 and 10 > a day. However all seem to be from google servers, although from several > different ones. > Check out https://bugs.exim.org/show_bug.cgi?id=2250 -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
