RE: [Exim] SMTP authentication

Hi

> yes, this is exactly what I have set up between Linux client in my school,
using a dial up connection (T-Online as access provider only) and my
server/smarthost, named "schule.de", using a fixed IP number.

Your "client" uses schule.de as smartrelay, i.e. it is sending mails over
schule.de which are for other domains.

> Now authentication (username and password) is necessary for deliver mails
from client to server.

Otherwise, if you could send without authentification, others could also do
so, in fact any spamer could.

> But I wonder, why my server can get mails from many other internet hosts
whithout authentication.

It will accept mails FOR schule.de. Otherwise, I wouldn't accept any mail
for you.

> Note, I manager the server "schule.de" too.

But, if you manage that server, you should have configured exim on it and
you should know its configuration.

cu
Steffen