|Depends on the site you are working with (I have seen this with stock trading) they could be doing MAC checks via the browser in combination with IP checking to that account. In the past, ultimately (for the trading scenario) they needed multiple internet connections, so we had multiple different static IP's to work with, easy to get multiple accounts. But if you have one internet connection, you can request a block of IP's and route traffic over specific IP's (usually multiple LAN's as well). |
But to determine "how" to make this work, we would need to know what the web server / company is doing authentication on the account.