I hope someone can help me with this please.
One of our clients has an in-house Postfix mailserver which basically downloads mail for the individual users from our mail server hosted on the web using fetchmail. They use our SMTP server to send mail. Their email clients are then setup to get & send mail from the server, on 192.168.2.254 (for POP3 & SMTP). All mail between them on the local LAN gets send to each other via the server, and not the internet.
This works quite well, but as soon as someone sends mail from the Linux server directly (it has webmin + usermin installed and has a basic webmail interface for when they're out of the office) it sends mail using the local machine name, instead of the domain name. for example, mail comes from firstname.lastname@example.org.
How do I tell Postfix to automaticlly send mail from @<theirdomain.com> instead?
Sorry for asking this, but I don't know Postfix very well and don't know what to call to, to search on google.