Warning about invalid sendmail option at startup

[Nicolas Galler]

Hi,

I just replaced sendmail with postfix. Works great, but I get this warning at
boot time (right after starting sshd, though I dont see why it would be
related to ssh):
sendmail: illegal option -- O
sendmail: fatal: usage: sendmail [option]

So obviously the postfix sendmail replacement program doesn't take the -O
option (whatever this does). I remember having the same message with qmail
before, too. How do I know where this warning comes from so that I can correct
the sendmail invocation?

Thanks
Nicolas Galler