Title: RE: [ActiveDir] ProxyAddress Verification Tools

In regards to SMTP address validity checking, you have to be very careful about the use the “.” character.  It must not be followed by another one (unless it is escaped) and can’t come at the end of the mail alias either.

 

Validity checking is best done by checking the syntax of the alias and then checking the syntax of DNS host name separately (which is another whole can of worms).

 

I have a pretty decent .NET regex that I use that seems to catch most invalid SMTP addresses with no false positives that I’ve seen yet.  I’m not sure it is perfect though.

 

Do you have a regex library you can use in your C++ utilities?  You could also do the parsing by hand, but that seems like it would much harder.

 

Joe K.

 


From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mulnick, Al
Sent: Thursday, November 04, 2004 10:20 AM
To: [EMAIL PROTECTED]
Subject: RE: [ActiveDir] ProxyAddress Verification Tools

 

Is there a good doc on SMTP address validity checking? I looked at one RFC but that is one of the more confusing RFCs I have read, don't recall which it was but the valid chars were on I think pages 8/9.

>>>The RFC's and the MSDN/KB docs (we're talking about Exchange right?) are the ones that count. When in doubt, MSDN/KB trumps the RFC although I would argue that if you let your company talk on the internet you should follow the least common denominator which is the RFC.  That prevents fun problems with foreign mailers.  Pretty much anything with 8-bit ASCII or 7-bit ASCII (included mostly in 8-bit right?) would be a valid character, and pretty much anything with at least a RHS and LHS of a mail address separated by "@" or "!" should be considered valid.  The docs have the details though.

You would think this would be better in a day and age when spam is so prevalent and many mailers (qmail for example) try to check for valid addresses.  Syntax checking should be so easy for them to check prior to checking for a valid recipient.  It's also in the Sendmail code to check in the routing and I would guess that Exchange does the same rather than look for an absolute match first.  The UA often makes some checks as well, so you may find something useful if you dig in those docs (evolution might be good since it's opensource).

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