I followed a tutorial using the socket connection dkim-milter to sign my outgoing mail. I did it and the conf file loaded fine. But I discovered that my mail were not signed. I found many other tutorial advising to use inet:8891@localhost instead of socket. I thought maybe that could be the reason why it's not signed. I did all the config changes to my dkim-milter file and to my sendmail mc passed by m4 but since I changed S=/something/to/socket to S=inet:8891@localhost I get unkown configuration line.

exact error message containing the line is:

Starting sendmail: 554 5.0.0 /etc/mail/sendmail.cf: 
line 1: unknown configuration line "INPUT_MAIL_FILTER(dkim-milter, S=inet:8891@localhost)"

I discovered that the line

INPUT_MAIL_FILTER(dkim-milter, S=inet:8891@localhost)

get written as is in the sendmail.cf file upon m4 process. I doubt that this is the correct thing that should happen.

SOLUTION ?

I finally erased INPUT_MAIL_FILTER that was correctly commented out and past the option line I wanted after

include(`/usr/share/sendmail-cf/m4/cf.m4')dnl

I dont know what could be the reason but it now works.