Re^4: Practical e-mail address validation (flexes)

You appear to mean "directly before the @". Thanks for the clarification. Email::Valid::Loose further clarifies:

Email::Valid::Loose is a subclass of Email::Valid, which allows . (dot) before @ (at-mark). It is invalid in RFC822, but is commonly used in some of mobile phone addresses in Japan (like docomo.ne.jp or jp-t.ne.jp).

So the items identified so far:

• Allow /\.\@/
• Disallow /\@.*%/ (actually more, since you answered my question in the negative in a private /msg and promised more details later)
• Disallow CFWS w/in the address
• Require /\@.*\./
• Require /\.[a-zA-Z]{2,}$/
• Require RFC1035-compliant domain (except empty ones)
• Extend RFC1035 to allow domain labels that start with a digit
• Disallow quoting (usually of $local_part)
• Disallow escaping (usually of $local_part)
• Disallow /\+.*\@/
• Disallow "group"s (/$display_name:$mailbox_list;/)
• Disallow "name-addr" (/$display_name?$angle_addr/)
• Disallow "obs*" (obs-angle-addr, obs-mbox-list, obs-addr-list, obs-local-part, obs-domain)

[Limbic~Region]

tye,
They (email addresses with periods immediately preceding the @) were also very common by Microsoft Exchange back when I was working at the DoJ. I am not sure if M$ has become more compliant. I am going to be updating this node with a variety of other ways at attempting to exploit open relays and I will /msg you when complete.

Update: Rather than enumerate them myself, go to http://www.abuse.net/relay.html and test an MTA you believe to be secure. It shows you all the email addresses it uses to test with (from and to). I also realized I had the relay syntax wrong. It is [e-mail]. I have updated the prior node.

Update: I haven't provided a complete list of "rules" that I think such a theoretical module should include but having "John Smith"@example.com is another one that should be flexible. If I come up with more I will add them here but it has been a long time since I thought about such things. Oh, and I used to have to worry about non-SMTP addresses too like CC:Mail and GroupWise (fortunately not UUCP).