When configuring a fresh SUSE machine, I forgot one tiny detail resulting in Sendmail ok on 127.0.0.1 but not ip address.
Solution:
Please change in
/etc/sysconfig/mail
fromSMTPD_LISTEN_REMOTE="no"
to
SMTPD_LISTEN_REMOTE="yes"
then run
SuSEconfig
and
rcsendmail restart
–jeroen