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•Re^5: Please evaluate: RegEx for validating e-mail addresses

by merlyn (Sage)
on Sep 25, 2004 at 20:24 UTC ( [id://393843] : note . print w/replies, xml ) Need Help??

in reply to Re^4: Please evaluate: RegEx for validating e-mail addresses
in thread Please evaluate: RegEx for validating e-mail addresses

L-R, I think you're confusing "stuff that microsoft produces" with actual Mail Transfer Agents.

All internet MTAs that I'm aware of would have no problems understanding and delivering those addresses. Sendmail, qmail, postfix, exim, smail, qsmtpd, etc etc.

I will stand firm on chastising anyone that narrows "valid email" down to their own limited view of email. Follow the RFC, or don't play at all. If you want to "embrace and extend", please do that in the privacy of your own cubicle, not out in public.

I will also stand firm on chastising those (such as you, L-R) who support such narrow views. Please don't do that. It makes my job harder as well.

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

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Re^6: Please evaluate: RegEx for validating e-mail addresses
by Limbic~Region (Chancellor) on Sep 26, 2004 at 14:01 UTC
    Unfortunately I am no longer with the U.S. Dept. of Justice to give specific examples, but the list of all the internet MTAs you mentioned was in my experience quite limited. The gateway delt with many hundreds of thousands of emails a day. The gambit gamut of mail systems that they communicated with was quite large to include, but certainly not limited to, CC:Mail, (old) GroupWise, and your beloved Microsoft Exchange. Additionally, there are other prehistoric mail systems out there, home grown ones, etc that I assure you are not RFC compliant.

    When the problem was with a modern system, it was almost always do to administrative modification to prevent anti-impersonation and open-relay. Since I can't give specific examples of MTAs that do not accept RFC compliant email addresses, is a site dedicated to listing domains that don't think the rules of the internet apply to them (postmaster, DSN, etc).

    Finally, it is arguable that I am using MTA (Message Transfer Agent) too liberally. For instance in the case of CC:Mail and GroupWise, the internal mail system was not native SMTP and so the gateway/MTA had to additionally translate the incoming address to the native format. Or perhaps if the MTA is only accepting mail for a specific domain which happens to be a specific mail system - than it is not a true MTA. I will not argue except to say my original point was referring to specific situations. Admittedly, I should have been clear:

    • You are only validating "to" addresses for "incoming" emails
    • You are validating requests for new email accounts on your specific mail system

    Now that the context is known, the possibilities I presented are pointless.

    Cheers - L~R

    Update: Word correction thanks to Albannach