how to retrieve Mac and IP address from client network adapter by Asp.net

For the IP check here: http://www.etechpulse.com/2013/04/how-to-get-ip-address-aspnet.html[^].
But you can resolve it to MAC only if the server and the client are on the same VLAN - if there is no router between them. In this case you can use ARP protocol. Check here: http://www.news2news.com/vfp/?example=585&ver=vcs[^].
You could get MAC address from client side, but only in a platform and browser dependent way, thus not reliable in any form: http://www.nullskull.com/q/10054371/how-to-get-client-mac-address.aspx[^]. I don't know what your intentions with the MAC were, but I suggest you forget them. It is not good for identification. It is not even guaranteed to be unique - and can be changed in most NICs.

I don't think getting Mac will be that easy in many scenarios(I haven't tried it yet),but to retrieve client's IP address,you can do something like below.

string ip = Server.HtmlEncode(Request.UserHostAddress);

This will give you ip as a string.

Note:

You will get 127.0.0.1 every time if you run it from localhost.

Regards..