nanog mailing list archives

Re: Programmers with network engineering skills


From: Owen DeLong <owen () delong com>
Date: Mon, 12 Mar 2012 14:32:23 -0700


On Mar 12, 2012, at 2:12 PM, Keegan Holley wrote:

2012/3/12 Tei <oscar.vives () gmail com>

On 12 March 2012 09:59, Carlos Martinez-Cagnazzo <carlosm3011 () gmail com>
wrote:
Hey!

On 3/8/12 8:24 PM, Lamar Owen wrote:
On Monday, March 05, 2012 09:36:41 PM Jimmy Hess wrote:
...
  (16)  The default gateway's IP address is always 192.168.0.1
  (17) The user portion of E-mail addresses never contain special
characters like  "-" "+"  "$"   "~"  "."  ",", "[",  "]"
I've just had my ' xx AT cagnazzo.name' email address rejected by a web
form saying that 'it is not a valid email address'. So I guess point
(17) can be extended to say that 'no email address shall end in anything
different that .com, .net or the local ccTLD'

:=)

Carlos


Yea, I don't even know how programmers can get that wrong.  The regex
is not even hard or anything.



(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])


I bet it's even harder without the use of a search engine.

Whenever I've built code to check someone's email address on a form, I always just looked for the following:

1.      matches ^[^@]+@[A-Za-z0-0\-\.]+[A-Za-z]$
2.      The component to the right of the @ sign returns at least one A, AAAA, or MX record.

If it passed those two checks, I figured that was about as good as I could do without resorting to one of the following:
        1.      An incomprehensible and unmaintainable regex as the one above
        2.      Actually attempting delivery to said address

Owen



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