i want to post the form through codebehind and access the cookies and sessions

Question

i have two sites :

1. abc.com
2. xyz.com

the username/password for abc.com is : admin/admin

login page for abc.com is : abc.com/login.aspx

After correct login, the landing page is : abc.com/mypage.aspx

Now i need to use xyz.com for login

i need to enter the username/password in codebehind in xyz.com/delault.aspx

and it will check the login from abc.com/login.aspx and then redirect to abc.com/mypage.aspx

in xyz.com/default.aspx codebehind, the login process is automatic once the page has been load, and i can access the sessions that i get after the login.