how to validate special characters in mail address?

Hi all,
Good morning
i have requirement to validate special characters like (ä --> this is not a, this is a latin character).how to allow these characters using asp validator control. could you please let me know about this.
example: 
Räm@XYZ.com
above mail is not allowing while using asp validator control how to allow latin keywords in mail validation.


Regards
CVPrasad



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