Domain Name Regex List. A regular expression to extract domain or host names from email addresses for smtpd client restrictions in Postfix. The above regex captures.
1 It allows usernames with 1 or 2 alphanum characters or 3 chars can have -_ in the middle. The domain name is then followed by a period. The regular expression For domain names.
LEFT B4 FIND B4 9-1 Author.
The domain name is then followed by a period. The above regular expression matches domain names up to 255 characters long with one or more labels up to 63 characters long separated by dots and with a top-level domain of 2 to 63 characters. LEFT B4 FIND B4 9-1 Author. Suppose we need a quick way to get the domain name of the email addresses.