I'm using qmail on our server and we keep recieving "553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)". Our customers do recieve the same error, which is unfortunate. I know that I could add domain by domain into the "rcpthosts" file, but it's not possible to add every single domain.
Now my question is: Is there a way to allow every domain?
Setup smtp authentication for senders that need to use your server for sending email.
Allowing sending by domain would be easily exploitable by spammers.
If you don't know the IP address ranges to allow, or they are not consistent (for example internal corporate network), I recommend smtp authentication.
smtp authentication for sender is already set up. It's possible to send to domains I've added in "rcpthosts", so that might not be the reason.
Sorry if you meant something else. I'm quite new to the topic.
Are you having trouble sending or receiving email? Is this an MX server, outgoing smtp relay, or both?
It sounds like smtp authentication is not setup correctly, your users outgoing mail server settings are not setup correctly, or the incoming email for some domains you host is not setup correctly.
It's wrong to be adding domains that you want to send to to the rcpthosts file, you're creating a partial open relay that can be abused by spammers.
Something is wrong with your smtp authentication configuration. A correct username and password should be all your users need to send email to any email address.