ether1 = wan (connected with DSL modem)
ether2 = lan (connected with user switch)
Clients (MAC MAIL OS X) behind mikrotik are unable to send emails via remote smtp server. Very rare it works, but most of the time unable to connect with the smtp, ping to smtp works fine. Tried to change mikrotik versions from 6.5 / 6.24 / 6.35.1, with no success.
On the other side, when user try to send email with outlook it works fine. Very Strange !
At the same time when I replace mikrotik with simple TPLINK router, the emails works fine all the time from MAC clients.
Initially I suspected maybe its something with the MTU, but i tried various MTU like 1500, 700, 14xx but none worked.
Code: Select all
/ip firewall mangle
add action=change-mss chain=forward disabled=no new-mss=XXX protocol=tcp \
tcp-flags=syn