How-to use external smtp server ?

[kilburn]

Setting otugoing mail relays for specific domains *can* be done, but it involves a great deal of postfix's custom configuration, and I'm not sure about how well this will play with ispcp's settings.

Nevertheless, what you need to do is add a new directive "sender_dependent_relayhost_maps = /etc/postfix/sender_dependent_relay". Thereafter, create the referenced file and write there something like "@domain.tld smtp:[your.provider.smtp.host]" (brackets must be there). Postmap this file and restart postfix.

By doing this, postfix will use "your.provider.smtp.host" as an outgoing relay whenever mails come from "xxxx@domain.tld" users. Additionally, you will probably also have to add these directives to main.cf:

Code:

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd

And write the user/password combination to identify against your isp's smtp server in the "/etc/postfix/sasl_passwd" file (that must also be postmapped). It should contain something like:

Code:

[your.provider.smtp.host]    user:password

Restart postfix and it will identify as this user whenever relaying mails through your isp's smtp server.