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Sunday, October 24, 2010

GMail mishandles e-mail addresses - '.' is insignificant in GMail

Tonight, I received a spam mail sent to A.BCD.HelloWorld@gmail.com and intrigued how it could arrive in the in box of ABCD.HelloWorld@Gmail.com my proper GMail account.

BTW, the above e-mail addresses are fictitious containing only structural information, like the presence or absence of a . to illustrate how GMail mishandling e-mail addresses.

So I did some experiments. I sent an e-mail from my hotmail account to A.BCD.HelloWorld@gmail.com and lo and behold, it arrived in ABCD.HelloWorld@gmail.com.

I did that with several other GMail accounts some with no '.' in the address and I could add as many '.' as I like and they were obediently sent to the address without '.'.

I took my other GMail account like this OneBrownFox@gmail.com and sent e-mail to O.n.e.B.r.o.w.n.F.o.x@gmail.com and without failing it ended up in OneBrownFox@gmail.com.

In other words, GMail tries to guess e-mail addresses and that kind of dangerous practices can increase the SPAM mail you receive. In E-Mail format, the '.' is significant. That is OneBrownFox@gmail.com and One.BrownFox@gmail.com are two distinct e-mail addresses with distinct inboxes. But in the eyes of GMail, they are not.

So far GMail is the only e-mail service that seems to mishandle e-mail address in this manner.

1 comment:

L. Mar said...

As it turns out this is actually a feature of GMail.

GMail strips out all '.' before sending it to your inbox. So to GMail the '.' is insignificant. In other words, you real GMail e-mail address is one with all '.' removed.

This is permitted in RFC2822 "3.4.1. Addr-spec specification".

An addr-spec is a specific Internet identifier that contains a locally interpreted string followed by the at-sign character ("@", ASCII value 64) followed by an Internet domain. The locally interpreted string is either a quoted-string or a dot-atom. If the string can be represented as a dot-atom (that is, it contains no characters other than atext characters or "." surrounded by atext characters), then the dot-atom form SHOULD be used and the quoted-string form SHOULD NOT be used. Comments and folding white space SHOULD NOT be used around the "@" in the addr-spec.

Hence GMail is free to do whatever it wants to handle the local-part of the e-mail address.

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