find the smtp server host and port for send email in asp.net using c#

for sending email in asp.net i imported system.net.mail namespace.


in web.config file i configured system.net settings.it is asking my smtp server host and port.i dont know how to find the my systems smtp server host and port.
for that purpose i gave localhost and port no is 465.but it shows error failure mail sending .
for overcome this error what should i do.

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