relay_domains how to deliver to any domain?

I'm a beginner and am trying to configure my sendmail on a RedHat linux box so that I dont need to update my /etc/mail/relay-domains each time I or people using my smtp.server send their mail to somebody on a new domain mashin.

The question I'm asking myself is how do the real ISP 's configure their sendmail relay - Most surely they are not updating their /etc/mail/relay-domains -files to
put the relaying of their user's emails to the different domains of the world. There must be some wild -cards option or something...? But wild cards don't work in config files in the /etc/mail -directory!

If it was the topic you were busy some time ago, and found an answer, or you are a Webmaster yourself -it would be greate if you could help.

I did look through an ISP-Services-HOWTO but
they say /etc/host.allow schold have a line like:

sendmail: .com .org usw...

I've pu it in but it don't seem to work.



Wish you all well

leon_navajo@addcom.de

You should look at POP before SMTP

The sender has to check their e-mail before they can use the SMTP server

Regards
Darren

yes the pop is something I didnt gave a thorough attention to. I'll look it better more carefully through.
thanx!

to carpediem
but problem is that sendmail rejects sending the mail to the new and not yet decleared in /etc/mail/relay-domains file domains. And that is a really nasty thing to ask your
people: "what domains are you people going to send your (perhaps private) mail to?"

bye receiving the mail there comes no "relay denied" rejection ind goes smooth and lightly!

The way it works is when somebody checks their POP account their IP address is logged and stored for a few mins'.

When they send via SMTP it checks the file containing the IP address, if the senders IP matches it then allows the mail to be sent else it wont send it

Darren

you are perfectly right david,
the place were I've found the solvation of the problem was
/etc/mail/access. On should give there .com .org .net usw.
to allow the smtp to relay the mail for every domain eith those endings or restrict it with the option -reject-.
but your answer about how the mail server cheks the domain suffix of the e-mail address has showed me the way, that I schould chek how it cheks, and there was the answer thank you!