Roundcube says "invalid email address"

[taylor85p]

I am not able to send email to some email with underscore in the domain name and some tld’s.
eg: abc@abc_defg.com

I have attached image sample as roundcube says “invalid email address”

How can i fix it in postfix or how to get this done?

Thank you

[openletter]

@taylor85p

abc_defg.com

Do you have an example of a valid domain name that uses _? I’ve never seen it before, and can’t find one when trying to search for it.

[alento]

@taylor85p

I am not able to send email to some email with underscore in the domain name and some tld’s.

That is because an underscore _ is not a valid character in a domain name. Only letters, numerals, and hyphens - are valid characters in non-internationalized domain names.

[ravenstar68]

The only symbol allowed in a domain name is a hyphen, and that has to come in the middle of the name.

Thus some-domain.com is a valid domain name while
some_domain.com is not a valid domain

In short, there’s nothing wrong with roundcube rejecting an email address@some_domain.com, it’s proper behaviour.

Tim

https://www.saveonhosting.com/scripts/index.php?rp=/knowledgebase/52/What-are-the-valid-characters-for-a-domain-name-and-how-long-can-a-domain-name-be.html#:~:text=A%20domain%20name%20can%20be,hyphen%20nor%20have%20consecutive%20hyphens.