METU E-List Admin wrote:
$ bin/config_list -o - REGISTER | grep -A20 header_filter_rules header_filter_rules = [('^X-Mailer: (?!Microsoft Outlook .*)$', 7,
This regexp won't work. The negative lookahead does not advance the current position so your regexp says look for 'X-Mailer: ' at the beginning of the line not followed by 'Microsoft Outlook .*' but followed immediately by the end of the line, so it will only match a header like 'X-Mailer: ' not followed by anything.
What you want is
^X-Mailer: (?!Microsoft Outlook .*).*$
or just
^X-Mailer: (?!Microsoft Outlook .*)
or maybe even just
^X-Mailer: (?!Microsoft Outlook )
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan