diff --git a/config/filter.d/sendmail-spam.conf b/config/filter.d/sendmail-spam.conf
index d4d812c7..c1477700 100644
--- a/config/filter.d/sendmail-spam.conf
+++ b/config/filter.d/sendmail-spam.conf
@@ -11,10 +11,20 @@ before = common.conf
 
 _daemon = sendmail
 
-failregex = ^(?P<__prefix>%(__prefix_line)s\w+: )<\w+@[\w.-]+>\.\.\. No such user here<SKIPLINES>(?P=__prefix)from=<\w+@[\w.-]+>, size=\d+, class=\d+, nrcpts=\d+, bodytype=\w+, proto=E?SMTP, daemon=MTA, relay=[\w.-]+ \[<HOST>\]$
+failregex = ^(?P<__prefix>%(__prefix_line)s\w+: )<[^@]+@[^>]+>\.\.\. No such user here<SKIPLINES>(?P=__prefix)from=<[^@]+@[^>]+>, size=\d+, class=\d+, nrcpts=\d+, bodytype=\w+, proto=E?SMTP, daemon=MTA, relay=\S+ \[<HOST>\]$
 
 [Init]
 
 # "maxlines" is number of log lines to buffer for multi-line regex searches
 maxlines = 10
 
+# DEV NOTES:
+# 
+# There can be a nunber of non-related lines between the first and second part
+# of this regex maxlines of 10 is quite generious. Only one of the 
+# "No such user" lines needs to be matched before the line with the HOST.
+#
+# Note the capture __prefix, includes both the __prefix_lines (which includes
+# the sendmail PID), but also the \w+ which the the sendmail assigned mail ID.
+#
+# Author: Daniel Black